A high microwave performance enhancement-mode(E-mode)In_(0.4)Ga_(0.6)As channel metal-oxide-semiconductor field-effect transistor(MOSFET)with a Si-doped In_(0.49)Ga0.51P interfacial layer is fabricated.A 0.8-μm-gate-...A high microwave performance enhancement-mode(E-mode)In_(0.4)Ga_(0.6)As channel metal-oxide-semiconductor field-effect transistor(MOSFET)with a Si-doped In_(0.49)Ga0.51P interfacial layer is fabricated.A 0.8-μm-gate-length In_(0.4)Ga_(0.6)As MOSFET with a 5-nm Al_(2)O_(3) dielectric layer provides a current gain cutoff frequency of 16.7 GHz and a maximum oscillation frequency of 52 GHz.A semi-empirical small-signal-parameter extraction technique accounting for the low frequency anomaly of this MOSFET device is described,which is based on on-wafer S-parameter measurements.Excellent agreement between measured and simulated scattering parameters as well as the physically realistic circuit elements demonstrates the validity of this approach.展开更多
Human beings are often affected by a wide range of skin diseases,which can be attributed to genetic factors and environmental influences,such as exposure to sunshine with ultraviolet(UV)rays.If left untreated,these di...Human beings are often affected by a wide range of skin diseases,which can be attributed to genetic factors and environmental influences,such as exposure to sunshine with ultraviolet(UV)rays.If left untreated,these diseases can have severe consequences and spread,especially among children.Early detection is crucial to prevent their spread and improve a patient’s chances of recovery.Dermatology,the branch of medicine dealing with skin diseases,faces challenges in accurately diagnosing these conditions due to the difficulty in identifying and distinguishing between different diseases based on their appearance,type of skin,and others.This study presents a method for detecting skin diseases using Deep Learning(DL),focusing on the most common diseases affecting children in Saudi Arabia due to the high UV value in most of the year,especially in the summer.The method utilizes various Convolutional Neural Network(CNN)architectures to classify skin conditions such as eczema,psoriasis,and ringworm.The proposed method demonstrates high accuracy rates of 99.99%and 97%using famous and effective transfer learning models MobileNet and DenseNet121,respectively.This illustrates the potential of DL in automating the detection of skin diseases and offers a promising approach for early diagnosis and treatment.展开更多
Tung＇s model was used to analyze anomalies observed in Ti/Si C Schottky contacts. The degree of the inhomogeneous Schottky barrier after annealing at different temperatures is characterized by the ‘T0anomaly＇ and t...Tung＇s model was used to analyze anomalies observed in Ti/Si C Schottky contacts. The degree of the inhomogeneous Schottky barrier after annealing at different temperatures is characterized by the ‘T0anomaly＇ and the difference（△Φ）between the uniformly high barrier height（Φ0B） and the effective barrier height（Φeff B）. Those two parameters of Ti Schottky contacts on 4H–Si C were deduced from I–V measurements in the temperature range of 298 K–503 K. The increase in Schottky barrier（SB） height（ΦB） and decrease in the ideality factor（n） with an increase measurement temperature indicate the presence of an inhomogeneous SB. The degree of inhomogeneity of the Schottky barrier depends on the annealing temperature, and it is at its lowest for 500-°C thermal treatment. The degree of inhomogeneity of the SB could reveal effects of thermal treatments on Schottky contacts in other aspects.展开更多
In0.4Ga0.6As channel metal-oxide-semiconductor field-effect transistors （MOSFETs） with and without an Si-doped In0.49Ga0.51P barrier layer grown on semi-insulating GaAs substrates have been investigated for the firs...In0.4Ga0.6As channel metal-oxide-semiconductor field-effect transistors （MOSFETs） with and without an Si-doped In0.49Ga0.51P barrier layer grown on semi-insulating GaAs substrates have been investigated for the first time. Compared with the In0.4Ga0.6As MOSFETs without an In0.49Ga0.51P barrier layer, In0.4Ga0.6As MOSFETs with an In0.49Ga0.51P barrier layer show higher drive current, higher transconductance, lower gate leakage current, lower subthreshold swing, and higher effective channel mobility. These In0.4Ga0.6As MOSFETs （gate length 2 μm） with an In0.49Ga0.51P barrier layer exhibit a high drive current of 117 mA/mm, a high transconductance of 71.9 mS/mm, and a maximum effective channel mobility of 1266 cm2/（V·s）.展开更多
In this paper, Al2O3 ultrathin film used as the surface passivation layer for A1GaN/GaN high electron mobility transistor （HEMT） is deposited by thermal atomic layer deposition （ALD）, thereby avoiding plasma-induc...In this paper, Al2O3 ultrathin film used as the surface passivation layer for A1GaN/GaN high electron mobility transistor （HEMT） is deposited by thermal atomic layer deposition （ALD）, thereby avoiding plasma-induced damage and erosion to the surface. A comparison is made between the surface passivation in this paper and the conventional plasma enhanced chemical vapor deposition （PECVD） SiN passivation. A remarkable reduction of the gate leakage current and a significant increase in small signal radio frequency （RF） performance are achieved after applying Al2O3＋BCB passivation. For the Al2O3＋BCB passivated device with a 0.7μm gate, the value of fmax reaches up to 100 GHz, but it decreases to 40 GHz for SiN HEMT. The fmax/ft ratio （〉 4） is also improved after Al2O3＋BCB passivation. The capacitancevoltage （C-V） measurement demonstrates that Al2O3＋BCB HEMT shows quite less density of trap states （on the order of magnitude of 1010 cm-2） than that obtained at commonly studied SiN HEMT.展开更多
The diffusion behavior of Cu and Ni atoms undergoing liquidesolid electromigration（L-S EM） was investigated using Cu/Sn/Ni interconnects under a current density of 5.0 103A/cm2 at 250℃. The flowing direction of ele...The diffusion behavior of Cu and Ni atoms undergoing liquidesolid electromigration（L-S EM） was investigated using Cu/Sn/Ni interconnects under a current density of 5.0 103A/cm2 at 250℃. The flowing direction of electrons significantly influences the cross-solder interaction of Cu and Ni atoms, i.e., under downwind diffusion, both Cu and Ni atoms can diffuse to the opposite interfaces; while under upwind diffusion,Cu atoms but not Ni atoms can diffuse to the opposite interface. When electrons flow from the Cu to the Ni, only Cu atoms diffuse to the opposite anode Ni interface, resulting in the transformation of interfacial intermetallic compound（IMC） from Ni3Sn4into（Cu,Ni）6Sn5and further into [（Cu,Ni）6Sn5t Cu6Sn5], while no Ni atoms diffuse to the opposite cathode Cu interface and thus the interfacial Cu6Sn5 remained.When electrons flow from the Ni to the Cu, both Cu and Ni atoms diffuse to the opposite interfaces,resulting in the interfacial IMC transformation from initial Cu6Sn5into（Cu,Ni）6Sn5and further into[（Cu,Ni）6Sn5t（Ni,Cu）3Sn4] at the anode Cu interface while that from initial Ni3Sn4into（Cu,Ni）6Sn5and further into（Ni,Cu）3Sn4at the cathode Ni interface. It is more damaging with electrons flowing from the Cu to the Ni than the other way.展开更多
From the beginning,the process of research and its publication is an ever-growing phenomenon and with the emergence of web technologies,its growth rate is overwhelming.On a rough estimate,more than thirty thousand res...From the beginning,the process of research and its publication is an ever-growing phenomenon and with the emergence of web technologies,its growth rate is overwhelming.On a rough estimate,more than thirty thousand research journals have been issuing around four million papers annually on average.Search engines,indexing services,and digital libraries have been searching for such publications over the web.Nevertheless,getting the most relevant articles against the user requests is yet a fantasy.It is mainly because the articles are not appropriately indexed based on the hierarchies of granular subject classification.To overcome this issue,researchers are striving to investigate new techniques for the classification of the research articles especially,when the complete article text is not available(a case of nonopen access articles).The proposed study aims to investigate the multilabel classification over the available metadata in the best possible way and to assess,“to what extent metadata-based features can perform in contrast to content-based approaches.”In this regard,novel techniques for investigating multilabel classification have been proposed,developed,and evaluated on metadata such as the Title and Keywords of the articles.The proposed technique has been assessed for two diverse datasets,namely,from the Journal of universal computer science(J.UCS)and the benchmark dataset comprises of the articles published by the Association for computing machinery(ACM).The proposed technique yields encouraging results in contrast to the state-ofthe-art techniques in the literature.展开更多
To achieve a high-quality high-κ/Ge interfaces for high hole mobility Ge p-MOSFET applications, a simple chemical cleaning and surface passivation scheme is introduced, and Ge p-MOSFETs with effective channel hole mo...To achieve a high-quality high-κ/Ge interfaces for high hole mobility Ge p-MOSFET applications, a simple chemical cleaning and surface passivation scheme is introduced, and Ge p-MOSFETs with effective channel hole mobility up to 665 cm2/V.s are demonstrated on a Ge （111） substrate. Moreover, a physical model is proposed to explain the dipole layer formation at the metal-oxide-semiconductor （MOS） interface by analyzing the electrical characteristics of HCl- and （NH4）2S-passivated samples.展开更多
Charge trapping behavior and its origin in Al2O3/SiC MOS structure are investigated by analyzing the capacitance–voltage(C–V) hysteresis and the chemical composition of the interface. The C–V hysteresis is measured...Charge trapping behavior and its origin in Al2O3/SiC MOS structure are investigated by analyzing the capacitance–voltage(C–V) hysteresis and the chemical composition of the interface. The C–V hysteresis is measured as a function of oxide thickness series for an Al2O3/SiC MIS capacitor. The distribution of the trapped charges, extracted from the C–V curves, is found to mainly follow a sheet charge model rather than a bulk charge model. Therefore, the electron injection phenomenon is evaluated by using linear fitting. It is found that most of the trapped charges are not distributed exactly at the interface but are located in the bulk of the Al2O3 layers, especially close to the border. Furthermore, there is no detectable oxide interface layer in the x-ray photoelectron spectroscope(XPS) and transmission electron microscope(TEM)measurements. In addition, Rutherford back scattering(RBS) analysis shows that the width of the Al2O3/SiC interface is less than 1 nm. It could be concluded that the charge trapping sites in Al2O3/SiC structure might mainly originate from the border traps in Al2O3 film rather than the interface traps in the interfacial transition layer.展开更多
We demonstrate high-performance In0.23 Ga0.77 As channel metal-oxide-semiconductor field-effect transistors （ MOS- FETs） with high on-current to off-current （Ion/Ioff） ratio grown on semi-insulating GaAs wafers by...We demonstrate high-performance In0.23 Ga0.77 As channel metal-oxide-semiconductor field-effect transistors （ MOS- FETs） with high on-current to off-current （Ion/Ioff） ratio grown on semi-insulating GaAs wafers by metal-organic chemical vapor deposition （MOCVD）. The 2μm channel-length devices exhibit a peak extrinsic transeonductance of 150 mS/mm and a drain current up to 500 mA/mm. The maximum effective mobility is 1680 cm2/Vs extracted by the split C-V method. Furthermore, the Ion/Ioff ratio is significantly improved from approximately 4.5 × 10^3 up to approximately 4.32 × 10^4 by controlling the etch thickness of In0.49Ga0.51P, The high drain current and high Ion/Ioff ratio of the In0.23Ga0.77As channel MOSFETs are achieved due to the high effective mobility and the low gate leakage current density.展开更多
Heterogeneous integration of crystalline Ge layers on cleaned and H-terminated Si(111)substrates are demonstrated by employing a combination of e-beam evaporation and solid phase epitaxy techniques.High-quality single...Heterogeneous integration of crystalline Ge layers on cleaned and H-terminated Si(111)substrates are demonstrated by employing a combination of e-beam evaporation and solid phase epitaxy techniques.High-quality single crystalline Ge(111)layers on Si(111)substrates with a smooth Ge surface and an abrupt interface between Ge and Si are obtained.An XRD rocking curve scan of the Ge(111)diffraction peak shovs a FWHM of only 260 arcsec for a 50-nm-thick Ge layer annealed at 600℃with a ramp-up rate of 20℃/s and a holding time of 1 min.The AFM images exhibit that the rms surface roughness of all the crystalline Ge layers are less than 2.1 nm.展开更多
The solid phase reactions of Ni with GaAs substrates are investigated.The experimental results reveal that the Ni-GaAs solid phase reaction forms a ternary phase of Ni2GaAs when annealing temperatures are in the range...The solid phase reactions of Ni with GaAs substrates are investigated.The experimental results reveal that the Ni-GaAs solid phase reaction forms a ternary phase of Ni2GaAs when annealing temperatures are in the range 250 300℃.As the annealing temperature increases to 400℃,the Ni2GaAs phase starts to decompose due to NiAs phase precipitation.Ni-GaAs alloys processed at 400℃ with a 3min annealing time demonstrate a sheet resistance of 30Ω/square after unreacted Ni removal in hot diluted-HCl solutions.Therefore,Ni-GaAs alloys formed by solid phase reaction could be promising metallic source/drain structures with significant low series resistance for high mobility Ⅲ-Ⅴ metal-oxide-semiconductor field effect transistor (MOSFET) applications.展开更多
We propose a modified thermal oxidation method in which an Al2O3 capping layer is used as an oxygen blocking layer （OBL） to form an ultrathin GeOx interracial layer, and obtain a superior Al2O3/GeOx/Ge gate stack. T...We propose a modified thermal oxidation method in which an Al2O3 capping layer is used as an oxygen blocking layer （OBL） to form an ultrathin GeOx interracial layer, and obtain a superior Al2O3/GeOx/Ge gate stack. The GeOx interfacial layer is formed in oxidation reaction by oxygen passing through the Al2O3 OBL, in which theAl2O3 layer could restrain the oxygen diffusion and suppress the GeO desorption during thermal treatment. The thickness of the GeOx interfacial layer would dramatically decrease as the thickness of Al2O3 OBL increases, which is beneficial to achieving an ultrathin GeOx interfacial layer to satisfy the demand for small equivalent oxide thickness （EOT）. In addition, the thickness of the GeOx interfacial layer has little influence on the passivation effect of the Al2O3/Ge interface. Ge （100） p-channel metal- oxide-semiconductor field-effect transistors （pMOSFETs） using the Al2O3/GeOx/Ge gate stacks exhibit excellent electrical characteristics; that is, a drain current on-off （Ionloft） ratio of above 1 104, a subthreshold slope of - 120 mV/dec, and a peak hole mobility of 265 cm2/V.s are achieved.展开更多
Surface treatment for Ge substrates using hydrogen chlorine cleaning and chemical passivation are investigated on AuTi/Al2O3/Ge metal-oxide-semiconductor capacitors.After hydrogen chlorine cleaning,a smooth Ge surface...Surface treatment for Ge substrates using hydrogen chlorine cleaning and chemical passivation are investigated on AuTi/Al2O3/Ge metal-oxide-semiconductor capacitors.After hydrogen chlorine cleaning,a smooth Ge surface almost free from native oxide is demonstrated by atomic force microscopy and x-ray photoelectron spectroscopy observations.Passivation using a hydrogen chlorine solution is found to form a chlorine-terminated surface,while aqueous ammonium sulfide pretreatment results in a surface terminated by Ge-S bonding.Compared with chlorine-passivated samples,the sulfur-passivated ones show less frequency dispersion and better thermal stability based on capacitance-voltage characterizations.The samples with HCl pre-cleaning and (NH4 )2S passivation show less frequency dispersion than the HF pre-cleaning and (NH4)2S passivated ones.The surface treatment process using hydrogen chlorine cleaning followed by aqueous ammonium sulfide passivation demonstrates a promising way to improve gate dielectric/Ge interface quality.展开更多
We demonstrate a high performance implant-free n-type In_(0.7)Ga_(0.3)As channel MOSFET with a 4-nm InP barrier layer fabricated on a semi-insulating substrate employing a 10-nm Al_(2)O_(3) as gate dielectric.The maxi...We demonstrate a high performance implant-free n-type In_(0.7)Ga_(0.3)As channel MOSFET with a 4-nm InP barrier layer fabricated on a semi-insulating substrate employing a 10-nm Al_(2)O_(3) as gate dielectric.The maximum effective channel mobility is 1862 cm^(2)/V·s extracted by the split C–V method.Devices with 0.8μm gate length exhibit a peak extrinsic transconductance of 85 mS/mm and a drive current of more than 200 mA/mm.A short-circuit current gain cutoff frequency f_(T) of 24.5 GHz and a maximum oscillation frequency f_(max) of 54 GHz are achieved for the 0.8μm gate-length device.The research is helpful to obtain higher performance In_(0.7)Ga_(0.3)As MOSFETs for radio-frequency applications.展开更多
The fabrication and characterization of 1700 V 7 A 4H-SiC vertical double-implanted metal-oxide-semiconductor field-effect transistors （VDMOSFETs） are reported. The drift layer is 17μm in thickness with 5 × 10...The fabrication and characterization of 1700 V 7 A 4H-SiC vertical double-implanted metal-oxide-semiconductor field-effect transistors （VDMOSFETs） are reported. The drift layer is 17μm in thickness with 5 × 10^15 cm^-3 n-type doping, and the channel length is 1μm. The MOSFETs show a peak mobility of 17cm2/V.s and a typical threshold voltage of 3 V. The active area of 0.028cm2 delivers a forward drain current of 7A at Vcs = 22 V and VDS= 15 V. The specific on-resistance （Ron,sv） is 18mΩ.cm2 at VGS= 22 V and the blocking voltage is 1975 V （IDS 〈 lOOnA） at VGS = 0 V.展开更多
GaSb is an attractive candidate for future high-performance Ⅲ-Ⅴ p-channel metal-oxide-semiconductor-field-effect-transistors(pMOSFETs)because of its high hole mobility.The effect of HCl based-chemical cleaning on re...GaSb is an attractive candidate for future high-performance Ⅲ-Ⅴ p-channel metal-oxide-semiconductor-field-effect-transistors(pMOSFETs)because of its high hole mobility.The effect of HCl based-chemical cleaning on removing the non-self limiting and instable native oxide layer of GaSb to obtain a clean and smooth surface has been studied.It is observed that the rms roughness of a GaSb surface is significantly reduced from 2.731 nm to 0.693 nm by using HCl:H_(2)O(1:3)solution.The Ni/Pt/Au ohmic contact exhibits an optimal specific contact resistivity of about 6.89×10^(-7)Ω·cm^(2) with a 60 s rapid thermal anneal(RTA)at 250℃.Based on the chemical cleaning and ohmic contact experimental results,inversion-channel enhancement GaSb pMOSFETs are demonstrated.For a 6μm gate length GaSb pMOSFET,a maximum drain current of about 4.0 mA/mm,a drain current on-off(ION/IOFF)ratio of>10^(3),and a subthreshold swing of~250 mV/decade are achieved.Combined with the split C-V method,a peak hole mobility of about 160 cm^(2)/V·s is obtained for a 24μm gate length GaSb pMOSFET.展开更多
This study investigates the suction and magnetic field effects on the two-dimensional nanofluid flow through a stretching/shrinking sheet at the stagnation point in the porous medium with thermal radiation.The governi...This study investigates the suction and magnetic field effects on the two-dimensional nanofluid flow through a stretching/shrinking sheet at the stagnation point in the porous medium with thermal radiation.The governing partial differential equations(PDEs)are converted into ordinary differential equations(ODEs)using the similarity transformation.The resulting ODEs are then solved numerically by using the bvp4c solver in MATLAB software.It was found that dual solutions exist for the shrinking parameter values up to a certain range.The numerical results obtained are compared,and the comparison showed a good agreement with the existing results in the literature.The governing parameters’effect on the velocity,temperature and nanoparticle fraction fields as well as the skin friction coefficient,the local Nusselt number and the Sherwood number are represented graphically and analyzed.The variation of the velocity,temperature and concentration increase with the increase in the suction and magnetic field parameters.It seems that the thermal radiation effect has increased the local Sherwood number while the local Nusselt number is reduced with it.展开更多
Since the first space probe flew to the Moon in 1959,over 200 deep-space exploration missions have already been carried out on the eight planets,various asteroids and comets in the solar system.Amount of deepspace sci...Since the first space probe flew to the Moon in 1959,over 200 deep-space exploration missions have already been carried out on the eight planets,various asteroids and comets in the solar system.Amount of deepspace scientific experiments promoted people to understand about the origin and evolution of the universe.展开更多
This paper presents a transient-enhanced NMOS low-dropout regulator （LDO） for portable applications with parallel feedback compensation. The parallel feedback structure adds a dynamic zero to get an adequate phase m...This paper presents a transient-enhanced NMOS low-dropout regulator （LDO） for portable applications with parallel feedback compensation. The parallel feedback structure adds a dynamic zero to get an adequate phase margin with a load current variation from 0 to 1 A. A class-AB error amplifier and a fast charging/discharging unit are adopted to enhance the transient performance. The proposed LDO has been implemented in a 0.35 μm BCD process. From experimental results, the regulator can operate with a minimum dropout voltage of 150 mV at a maximum 1 A load and IQ of 165 μA. Under the full range load current step, the voltage undershoot and overshoot of the proposed LDO are reduced to 38 mV and 27 mV respectively.展开更多
基金Supported by the National Basic Research Program of China under Grant Nos 2011CBA00605 and 2010CB327501the National Science&Technology Major Project under Grant No 2011ZX02708-003One Hundred Talents Program of Chinese Academy of Sciences,and the Scientific Research Foundation for the Returned Overseas Chinese Scholars,the Ministry of Education of China.
文摘A high microwave performance enhancement-mode(E-mode)In_(0.4)Ga_(0.6)As channel metal-oxide-semiconductor field-effect transistor(MOSFET)with a Si-doped In_(0.49)Ga0.51P interfacial layer is fabricated.A 0.8-μm-gate-length In_(0.4)Ga_(0.6)As MOSFET with a 5-nm Al_(2)O_(3) dielectric layer provides a current gain cutoff frequency of 16.7 GHz and a maximum oscillation frequency of 52 GHz.A semi-empirical small-signal-parameter extraction technique accounting for the low frequency anomaly of this MOSFET device is described,which is based on on-wafer S-parameter measurements.Excellent agreement between measured and simulated scattering parameters as well as the physically realistic circuit elements demonstrates the validity of this approach.
文摘Human beings are often affected by a wide range of skin diseases,which can be attributed to genetic factors and environmental influences,such as exposure to sunshine with ultraviolet(UV)rays.If left untreated,these diseases can have severe consequences and spread,especially among children.Early detection is crucial to prevent their spread and improve a patient’s chances of recovery.Dermatology,the branch of medicine dealing with skin diseases,faces challenges in accurately diagnosing these conditions due to the difficulty in identifying and distinguishing between different diseases based on their appearance,type of skin,and others.This study presents a method for detecting skin diseases using Deep Learning(DL),focusing on the most common diseases affecting children in Saudi Arabia due to the high UV value in most of the year,especially in the summer.The method utilizes various Convolutional Neural Network(CNN)architectures to classify skin conditions such as eczema,psoriasis,and ringworm.The proposed method demonstrates high accuracy rates of 99.99%and 97%using famous and effective transfer learning models MobileNet and DenseNet121,respectively.This illustrates the potential of DL in automating the detection of skin diseases and offers a promising approach for early diagnosis and treatment.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61106080 and 61275042)the National Science and Technology Major Project of the Ministry of Science and Technology of China(Grant No.2013ZX02305)
文摘Tung＇s model was used to analyze anomalies observed in Ti/Si C Schottky contacts. The degree of the inhomogeneous Schottky barrier after annealing at different temperatures is characterized by the ‘T0anomaly＇ and the difference（△Φ）between the uniformly high barrier height（Φ0B） and the effective barrier height（Φeff B）. Those two parameters of Ti Schottky contacts on 4H–Si C were deduced from I–V measurements in the temperature range of 298 K–503 K. The increase in Schottky barrier（SB） height（ΦB） and decrease in the ideality factor（n） with an increase measurement temperature indicate the presence of an inhomogeneous SB. The degree of inhomogeneity of the Schottky barrier depends on the annealing temperature, and it is at its lowest for 500-°C thermal treatment. The degree of inhomogeneity of the SB could reveal effects of thermal treatments on Schottky contacts in other aspects.
基金the National Basic Research Program of China(Grant Nos.2011CBA00605 and 2010CB327501)the National Natural Science Foundation of China(Grant No.61106095)the National Science and Technology Major Project of the Ministry of Science and Technology of China(Grant No.2011ZX02708-003)
文摘In0.4Ga0.6As channel metal-oxide-semiconductor field-effect transistors （MOSFETs） with and without an Si-doped In0.49Ga0.51P barrier layer grown on semi-insulating GaAs substrates have been investigated for the first time. Compared with the In0.4Ga0.6As MOSFETs without an In0.49Ga0.51P barrier layer, In0.4Ga0.6As MOSFETs with an In0.49Ga0.51P barrier layer show higher drive current, higher transconductance, lower gate leakage current, lower subthreshold swing, and higher effective channel mobility. These In0.4Ga0.6As MOSFETs （gate length 2 μm） with an In0.49Ga0.51P barrier layer exhibit a high drive current of 117 mA/mm, a high transconductance of 71.9 mS/mm, and a maximum effective channel mobility of 1266 cm2/（V·s）.
文摘In this paper, Al2O3 ultrathin film used as the surface passivation layer for A1GaN/GaN high electron mobility transistor （HEMT） is deposited by thermal atomic layer deposition （ALD）, thereby avoiding plasma-induced damage and erosion to the surface. A comparison is made between the surface passivation in this paper and the conventional plasma enhanced chemical vapor deposition （PECVD） SiN passivation. A remarkable reduction of the gate leakage current and a significant increase in small signal radio frequency （RF） performance are achieved after applying Al2O3＋BCB passivation. For the Al2O3＋BCB passivated device with a 0.7μm gate, the value of fmax reaches up to 100 GHz, but it decreases to 40 GHz for SiN HEMT. The fmax/ft ratio （〉 4） is also improved after Al2O3＋BCB passivation. The capacitancevoltage （C-V） measurement demonstrates that Al2O3＋BCB HEMT shows quite less density of trap states （on the order of magnitude of 1010 cm-2） than that obtained at commonly studied SiN HEMT.
基金financial support of the projects from the National Natural Science Foundation of China (Nos. 51475072 and 51171036)
文摘The diffusion behavior of Cu and Ni atoms undergoing liquidesolid electromigration（L-S EM） was investigated using Cu/Sn/Ni interconnects under a current density of 5.0 103A/cm2 at 250℃. The flowing direction of electrons significantly influences the cross-solder interaction of Cu and Ni atoms, i.e., under downwind diffusion, both Cu and Ni atoms can diffuse to the opposite interfaces; while under upwind diffusion,Cu atoms but not Ni atoms can diffuse to the opposite interface. When electrons flow from the Cu to the Ni, only Cu atoms diffuse to the opposite anode Ni interface, resulting in the transformation of interfacial intermetallic compound（IMC） from Ni3Sn4into（Cu,Ni）6Sn5and further into [（Cu,Ni）6Sn5t Cu6Sn5], while no Ni atoms diffuse to the opposite cathode Cu interface and thus the interfacial Cu6Sn5 remained.When electrons flow from the Ni to the Cu, both Cu and Ni atoms diffuse to the opposite interfaces,resulting in the interfacial IMC transformation from initial Cu6Sn5into（Cu,Ni）6Sn5and further into[（Cu,Ni）6Sn5t（Ni,Cu）3Sn4] at the anode Cu interface while that from initial Ni3Sn4into（Cu,Ni）6Sn5and further into（Ni,Cu）3Sn4at the cathode Ni interface. It is more damaging with electrons flowing from the Cu to the Ni than the other way.
文摘From the beginning,the process of research and its publication is an ever-growing phenomenon and with the emergence of web technologies,its growth rate is overwhelming.On a rough estimate,more than thirty thousand research journals have been issuing around four million papers annually on average.Search engines,indexing services,and digital libraries have been searching for such publications over the web.Nevertheless,getting the most relevant articles against the user requests is yet a fantasy.It is mainly because the articles are not appropriately indexed based on the hierarchies of granular subject classification.To overcome this issue,researchers are striving to investigate new techniques for the classification of the research articles especially,when the complete article text is not available(a case of nonopen access articles).The proposed study aims to investigate the multilabel classification over the available metadata in the best possible way and to assess,“to what extent metadata-based features can perform in contrast to content-based approaches.”In this regard,novel techniques for investigating multilabel classification have been proposed,developed,and evaluated on metadata such as the Title and Keywords of the articles.The proposed technique has been assessed for two diverse datasets,namely,from the Journal of universal computer science(J.UCS)and the benchmark dataset comprises of the articles published by the Association for computing machinery(ACM).The proposed technique yields encouraging results in contrast to the state-ofthe-art techniques in the literature.
基金Project supported by the National Basic Research Program of China (Grant Nos.2011CBA00605 and 2010CB327501)the National Natural Science Foundation of China (Grant No.61106095)the National Science and Technology Major Project of the Ministry of Science and Technology of China (Grant No.2011ZX02708-003)
文摘To achieve a high-quality high-κ/Ge interfaces for high hole mobility Ge p-MOSFET applications, a simple chemical cleaning and surface passivation scheme is introduced, and Ge p-MOSFETs with effective channel hole mobility up to 665 cm2/V.s are demonstrated on a Ge （111） substrate. Moreover, a physical model is proposed to explain the dipole layer formation at the metal-oxide-semiconductor （MOS） interface by analyzing the electrical characteristics of HCl- and （NH4）2S-passivated samples.
基金supported by the National Natural Science Foundation of China(Grant No.61106080)the National Science and Technology Major Project of the Ministry of Science and Technology of China(Grant No.2013ZX02305)
文摘Charge trapping behavior and its origin in Al2O3/SiC MOS structure are investigated by analyzing the capacitance–voltage(C–V) hysteresis and the chemical composition of the interface. The C–V hysteresis is measured as a function of oxide thickness series for an Al2O3/SiC MIS capacitor. The distribution of the trapped charges, extracted from the C–V curves, is found to mainly follow a sheet charge model rather than a bulk charge model. Therefore, the electron injection phenomenon is evaluated by using linear fitting. It is found that most of the trapped charges are not distributed exactly at the interface but are located in the bulk of the Al2O3 layers, especially close to the border. Furthermore, there is no detectable oxide interface layer in the x-ray photoelectron spectroscope(XPS) and transmission electron microscope(TEM)measurements. In addition, Rutherford back scattering(RBS) analysis shows that the width of the Al2O3/SiC interface is less than 1 nm. It could be concluded that the charge trapping sites in Al2O3/SiC structure might mainly originate from the border traps in Al2O3 film rather than the interface traps in the interfacial transition layer.
文摘We demonstrate high-performance In0.23 Ga0.77 As channel metal-oxide-semiconductor field-effect transistors （ MOS- FETs） with high on-current to off-current （Ion/Ioff） ratio grown on semi-insulating GaAs wafers by metal-organic chemical vapor deposition （MOCVD）. The 2μm channel-length devices exhibit a peak extrinsic transeonductance of 150 mS/mm and a drain current up to 500 mA/mm. The maximum effective mobility is 1680 cm2/Vs extracted by the split C-V method. Furthermore, the Ion/Ioff ratio is significantly improved from approximately 4.5 × 10^3 up to approximately 4.32 × 10^4 by controlling the etch thickness of In0.49Ga0.51P, The high drain current and high Ion/Ioff ratio of the In0.23Ga0.77As channel MOSFETs are achieved due to the high effective mobility and the low gate leakage current density.
基金Supported by the National Basic Research Program of China under Grant Nos 2011CB309605 and 2010CB327501the National Science&Technology Major Project of China under Grant No 2011ZX02708-003.
文摘Heterogeneous integration of crystalline Ge layers on cleaned and H-terminated Si(111)substrates are demonstrated by employing a combination of e-beam evaporation and solid phase epitaxy techniques.High-quality single crystalline Ge(111)layers on Si(111)substrates with a smooth Ge surface and an abrupt interface between Ge and Si are obtained.An XRD rocking curve scan of the Ge(111)diffraction peak shovs a FWHM of only 260 arcsec for a 50-nm-thick Ge layer annealed at 600℃with a ramp-up rate of 20℃/s and a holding time of 1 min.The AFM images exhibit that the rms surface roughness of all the crystalline Ge layers are less than 2.1 nm.
基金Supported by the National Basic Research Program of China under Grant Nos 2011CBA00605 and 2010CB327501the National Science&Technology Major Project of China under Grant No 2011ZX02708-003+1 种基金One-Hundred Talent Program of Chinese Academy of Sciencesthe Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of China.
文摘The solid phase reactions of Ni with GaAs substrates are investigated.The experimental results reveal that the Ni-GaAs solid phase reaction forms a ternary phase of Ni2GaAs when annealing temperatures are in the range 250 300℃.As the annealing temperature increases to 400℃,the Ni2GaAs phase starts to decompose due to NiAs phase precipitation.Ni-GaAs alloys processed at 400℃ with a 3min annealing time demonstrate a sheet resistance of 30Ω/square after unreacted Ni removal in hot diluted-HCl solutions.Therefore,Ni-GaAs alloys formed by solid phase reaction could be promising metallic source/drain structures with significant low series resistance for high mobility Ⅲ-Ⅴ metal-oxide-semiconductor field effect transistor (MOSFET) applications.
基金Project supported by the National Basic Research Program of China(Grant Nos.2011CBA00605 and 2011CBA00607)the National Natural Science Foundation of China(Grant No.61204103)the National Science & Technology Major Project of China(Grant No.2011ZX02708-003)
文摘We propose a modified thermal oxidation method in which an Al2O3 capping layer is used as an oxygen blocking layer （OBL） to form an ultrathin GeOx interracial layer, and obtain a superior Al2O3/GeOx/Ge gate stack. The GeOx interfacial layer is formed in oxidation reaction by oxygen passing through the Al2O3 OBL, in which theAl2O3 layer could restrain the oxygen diffusion and suppress the GeO desorption during thermal treatment. The thickness of the GeOx interfacial layer would dramatically decrease as the thickness of Al2O3 OBL increases, which is beneficial to achieving an ultrathin GeOx interfacial layer to satisfy the demand for small equivalent oxide thickness （EOT）. In addition, the thickness of the GeOx interfacial layer has little influence on the passivation effect of the Al2O3/Ge interface. Ge （100） p-channel metal- oxide-semiconductor field-effect transistors （pMOSFETs） using the Al2O3/GeOx/Ge gate stacks exhibit excellent electrical characteristics; that is, a drain current on-off （Ionloft） ratio of above 1 104, a subthreshold slope of - 120 mV/dec, and a peak hole mobility of 265 cm2/V.s are achieved.
基金Supported by the National Basic Research Program of China under Grant NoS 2011CBA00605 and 2010CB327501the National Science&Technology Major Project of China under Grant No 2011ZX02708-003,One Hundred Talents Program of Chinese Academy of Sciencesthe Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry.
文摘Surface treatment for Ge substrates using hydrogen chlorine cleaning and chemical passivation are investigated on AuTi/Al2O3/Ge metal-oxide-semiconductor capacitors.After hydrogen chlorine cleaning,a smooth Ge surface almost free from native oxide is demonstrated by atomic force microscopy and x-ray photoelectron spectroscopy observations.Passivation using a hydrogen chlorine solution is found to form a chlorine-terminated surface,while aqueous ammonium sulfide pretreatment results in a surface terminated by Ge-S bonding.Compared with chlorine-passivated samples,the sulfur-passivated ones show less frequency dispersion and better thermal stability based on capacitance-voltage characterizations.The samples with HCl pre-cleaning and (NH4 )2S passivation show less frequency dispersion than the HF pre-cleaning and (NH4)2S passivated ones.The surface treatment process using hydrogen chlorine cleaning followed by aqueous ammonium sulfide passivation demonstrates a promising way to improve gate dielectric/Ge interface quality.
基金Supported by the National Basic Research Program of China under Grant Nos 2011CBA00605,2010CB327501the National Science&Technology Major Project under Grant No 2011ZX02708-003One Hundred Talents Program of Chinese Academy of Sciences,and the Scientific Research Foundation for the Returned Overseas Chinese Scholars,the Ministry of Education of China.
文摘We demonstrate a high performance implant-free n-type In_(0.7)Ga_(0.3)As channel MOSFET with a 4-nm InP barrier layer fabricated on a semi-insulating substrate employing a 10-nm Al_(2)O_(3) as gate dielectric.The maximum effective channel mobility is 1862 cm^(2)/V·s extracted by the split C–V method.Devices with 0.8μm gate length exhibit a peak extrinsic transconductance of 85 mS/mm and a drive current of more than 200 mA/mm.A short-circuit current gain cutoff frequency f_(T) of 24.5 GHz and a maximum oscillation frequency f_(max) of 54 GHz are achieved for the 0.8μm gate-length device.The research is helpful to obtain higher performance In_(0.7)Ga_(0.3)As MOSFETs for radio-frequency applications.
基金Supported by the National Science and Technology Major Project of the Ministry of Science and Technology of China under Grant No 2013ZX02305
文摘The fabrication and characterization of 1700 V 7 A 4H-SiC vertical double-implanted metal-oxide-semiconductor field-effect transistors （VDMOSFETs） are reported. The drift layer is 17μm in thickness with 5 × 10^15 cm^-3 n-type doping, and the channel length is 1μm. The MOSFETs show a peak mobility of 17cm2/V.s and a typical threshold voltage of 3 V. The active area of 0.028cm2 delivers a forward drain current of 7A at Vcs = 22 V and VDS= 15 V. The specific on-resistance （Ron,sv） is 18mΩ.cm2 at VGS= 22 V and the blocking voltage is 1975 V （IDS 〈 lOOnA） at VGS = 0 V.
基金Supported by the National Basic Research Program of China under Grant Nos 2011CBA00605,2010CB327501the National Natural Science Foundation of China under Grant No 61106095+1 种基金the National Science&Technology Major Project of China under Grant No 2011ZX02708-003One Hundred Talents Program of Chinese Academy of Sciences,and the Scientific Research Foundation for the Returned Overseas Chinese Scholars,the Ministry of Education of China.
文摘GaSb is an attractive candidate for future high-performance Ⅲ-Ⅴ p-channel metal-oxide-semiconductor-field-effect-transistors(pMOSFETs)because of its high hole mobility.The effect of HCl based-chemical cleaning on removing the non-self limiting and instable native oxide layer of GaSb to obtain a clean and smooth surface has been studied.It is observed that the rms roughness of a GaSb surface is significantly reduced from 2.731 nm to 0.693 nm by using HCl:H_(2)O(1:3)solution.The Ni/Pt/Au ohmic contact exhibits an optimal specific contact resistivity of about 6.89×10^(-7)Ω·cm^(2) with a 60 s rapid thermal anneal(RTA)at 250℃.Based on the chemical cleaning and ohmic contact experimental results,inversion-channel enhancement GaSb pMOSFETs are demonstrated.For a 6μm gate length GaSb pMOSFET,a maximum drain current of about 4.0 mA/mm,a drain current on-off(ION/IOFF)ratio of>10^(3),and a subthreshold swing of~250 mV/decade are achieved.Combined with the split C-V method,a peak hole mobility of about 160 cm^(2)/V·s is obtained for a 24μm gate length GaSb pMOSFET.
基金the Fundamental Research Grant Scheme(FRGS)under a grant number of FRGS/1/2018/STG06/UNIMAP/02/3 from the Ministry of Education Malaysia。
文摘This study investigates the suction and magnetic field effects on the two-dimensional nanofluid flow through a stretching/shrinking sheet at the stagnation point in the porous medium with thermal radiation.The governing partial differential equations(PDEs)are converted into ordinary differential equations(ODEs)using the similarity transformation.The resulting ODEs are then solved numerically by using the bvp4c solver in MATLAB software.It was found that dual solutions exist for the shrinking parameter values up to a certain range.The numerical results obtained are compared,and the comparison showed a good agreement with the existing results in the literature.The governing parameters’effect on the velocity,temperature and nanoparticle fraction fields as well as the skin friction coefficient,the local Nusselt number and the Sherwood number are represented graphically and analyzed.The variation of the velocity,temperature and concentration increase with the increase in the suction and magnetic field parameters.It seems that the thermal radiation effect has increased the local Sherwood number while the local Nusselt number is reduced with it.
文摘Since the first space probe flew to the Moon in 1959,over 200 deep-space exploration missions have already been carried out on the eight planets,various asteroids and comets in the solar system.Amount of deepspace scientific experiments promoted people to understand about the origin and evolution of the universe.
文摘This paper presents a transient-enhanced NMOS low-dropout regulator （LDO） for portable applications with parallel feedback compensation. The parallel feedback structure adds a dynamic zero to get an adequate phase margin with a load current variation from 0 to 1 A. A class-AB error amplifier and a fast charging/discharging unit are adopted to enhance the transient performance. The proposed LDO has been implemented in a 0.35 μm BCD process. From experimental results, the regulator can operate with a minimum dropout voltage of 150 mV at a maximum 1 A load and IQ of 165 μA. Under the full range load current step, the voltage undershoot and overshoot of the proposed LDO are reduced to 38 mV and 27 mV respectively.
