Strained-Si0.73Ge0.27 channels are successfully integrated with high-R/metal gates in p-type metai-oxide- semi- conductor field effect transistors （pMOSFETs） using the replacement post-gate process. A silicon cap an...Strained-Si0.73Ge0.27 channels are successfully integrated with high-R/metal gates in p-type metai-oxide- semi- conductor field effect transistors （pMOSFETs） using the replacement post-gate process. A silicon cap and oxide inter layers are inserted between Si0.73Ge0.27 and high-κ dielectric to improve the interface. The fab- ricated Si0.73Ge0.27 pMOSFETs with gate length of 3Onto exhibit good performance with high drive current （~428μA/μm at VDD = 1 V） and suppressed short-channel effects （DIBL^77mV/V and SS^90mV/decade）. It is found that the enhancement of effective hole mobility is up to 200% in long-gate-length Si0.73Ge0.27-channel pMOSFETs compared with the corresponding silicon transistors. The improvement of device performance is reduced due to strain relaxation as the gate length decreases, while 26% increase of the drive current is still obtained for 30-nm-gate-length Si0.73Ge0.27 devices.展开更多
A high crystalline quality of SiGe fin with an Si-rich composition area using the replacement fin processing is systematically demonstrated in this paper.The fin replacement process based on a standard FinFET process ...A high crystalline quality of SiGe fin with an Si-rich composition area using the replacement fin processing is systematically demonstrated in this paper.The fin replacement process based on a standard FinFET process is developed.A width of less than 20-nm SiGe fin without obvious defect impact both in the direction across the fin and in the direction along the fin is verified by using the high angle annular dark field scanning transmission electron microscopy and the scanning moiréfringe imaging technique.Moreover,the SiGe composition is inhomogenous in the width of the fin.This is induced by the formation of 111 facets.Due to the atomic density of the 111 facets being higher,the epitaxial growth in the direction perpendicular to these facets is slower than in the direction perpendicular to 001.The Ge incorporation is then higher on the 111 facets than on the 001 facets.So,an Si-rich area is observed in the central area and on the bottom of SiGe fin.展开更多
A narrowed Si_(0.7)Ge_(0.3)channel fin field-effect transistor(FinFET)device is demonstrated in detail by using an accuratecyclic wet treatment process.The Si_(0.7)Ge_(0.3)fin/per side of 0.63 nm in thickness can be a...A narrowed Si_(0.7)Ge_(0.3)channel fin field-effect transistor(FinFET)device is demonstrated in detail by using an accuratecyclic wet treatment process.The Si_(0.7)Ge_(0.3)fin/per side of 0.63 nm in thickness can be accurately removed in each cycleby utilizing a self-limited oxidation with 40%HNO_(3)solution in 40 s and oxidation removal can be achieved with 1%HFsolution in 10 s.As a result,after the dummy gate removal,the fin width of Si_(0.7)Ge_(0.3)can be narrowed from 20 nm to 8 nmby utilizing 10 cycles of this wet treatment process.Compared with the conventional Si_(0.7)Ge_(0.3)FinFET under a similarprocess,the narrowed Si_(0.7)Ge_(0.3)channel FinFET can realize a strong gate control capability by using this newly developedwet treatment process,because its subthreshold slope can be reduced by 24%,improving from 87 mV/dec to 64 mV/dec.展开更多
In vertical channel transistors(VCTs),source/drain ion implantation(I/I)represents a significant technical challenge due to inherent three-dimensional structural constraints,which induce complications such as difficul...In vertical channel transistors(VCTs),source/drain ion implantation(I/I)represents a significant technical challenge due to inherent three-dimensional structural constraints,which induce complications such as difficulties in dummy gate forma-tion and shadowing effects of I/I.This article systematically investigates the impact of different implantation conditions on the performance of VCTs with and without dummy gates through TCAD simulation.It reveals the significant role of the lightly doped regions(LDRs)naturally formed due to ion implantation in source/drain of VCTs.Furthermore,it was found that VCT with-out dummy gates can achieve an approximately 27%increase in on-state current(Ion)under the same implantation conditions,and can greatly simplify the process flow and reduce costs.Finally,N-type and P-type VCTs were successfully fabricated using this implantation method.展开更多
The n-type ultrathin fully depleted silicon-on-insulator(FDSOI) metal-oxide-semiconductor field-effect transistors(MOSFETs),with a Hf_(0.5)Zr_(0.5)O_(2) high dielectric permittivity(high-k) dielectric as gate insulato...The n-type ultrathin fully depleted silicon-on-insulator(FDSOI) metal-oxide-semiconductor field-effect transistors(MOSFETs),with a Hf_(0.5)Zr_(0.5)O_(2) high dielectric permittivity(high-k) dielectric as gate insulator,were fabricated.The total ionizing dose effects were investigated,and an X-ray radiation dose up to 1500 krad(Si) was applied for both long-and short-channel devices.The short-channel devices(0.025-0.100 μm) exhibited less irradiation sensitivity compared with the long-channel devices(0.35-16 μm),leading to a 71% reduction in the irradiation-induced drain current growth and a 26% decrease in the shift of the threshold voltage.It was experimentally demonstrated that the OFF mode is the worst case among the three working conditions(OFF,ON and A110) for short-channel devices.Also,the determined effective electron mobility was enhanced by 38% after X-ray irradiation,attributed to the different compensations for charges triggered by radiation between the highk dielectric and buried oxide.By extracting the carrier mobility,gate length modulation,and source/drain(S/D)parasitic resistance,the degradation mechanism on X-ray irradiation was revealed.Finally,the split capacitance-voltage measurements were used to validate the analysis.展开更多
In order to effectively remove the residual Ge atoms at the surface of channel and improve the interfacial characteristic of gate-all-around(GAA)Si nanosheet field effect transistors,a low-temperature atomic-level tri...In order to effectively remove the residual Ge atoms at the surface of channel and improve the interfacial characteristic of gate-all-around(GAA)Si nanosheet field effect transistors,a low-temperature atomic-level trimming approach using ammonia peroxide water mixture(APM)solution treatment followed by diluted hydrofluoric acid is proposed and carried out.The capacitor samples with SiGe epitaxy layer,similar thermal budget and channel release process were fabricated using advanced high-k/metal-gate.An 83%reduction in surface roughness at atomic level is obtained by increasing APM treatment time.Moreover,there are 99.45% reduction in the interface state density(D_(it))and 96.8%leakage reduction in current density(J_(g))after APM treatment,indicating a promising method for future GAA NSFET performance optimization.展开更多
The dependence of perpendicular magnetic anisotropy （PMA） on the barrier layer MgO thickness in MgO/CoFeB /Ta multilayers is investigated. The results show that the strongest PMA occurs in a small window of about 2 ...The dependence of perpendicular magnetic anisotropy （PMA） on the barrier layer MgO thickness in MgO/CoFeB /Ta multilayers is investigated. The results show that the strongest PMA occurs in a small window of about 2 4nm with the increase of MgO thickness from 1-1Onto. The crystalline degree of MgO and the change of interatomic distance along the out-of-plane direction may be the main reasons for the change of PMA in these multilayers. Moreover, the roughnesses of 2- and 4-nm-thick MgO samples are 3.163 and 1.8 nm, respectively, and both the samples show PMA. These results could be used to tune the magnetic characteristic of the ultra thin CoFeB film for future applications in perpendicular magnetic devices.展开更多
A comprehensive study of the negative and positive bias temperature instability(NBTI/PBTI)of 3D FinFET devices with different small channel lengths is presented.It is found while with the channel lengths shrinking fro...A comprehensive study of the negative and positive bias temperature instability(NBTI/PBTI)of 3D FinFET devices with different small channel lengths is presented.It is found while with the channel lengths shrinking from 100 nm to 30 nm,both the NBTI characteristics of p-FinFET and PBTI characteristics of n-FinFET turn better.Moreover,the channel length dependence on NBTI is more serious than that on PBTI.Through the analysis of the physical mechanism of BTI and the simulation of 3-D stress in the FinFET device,a physical mechanism of the channel length dependence on NBTI/PBTI is proposed.Both extra fluorine passivation in the corner of bulk oxide and stronger channel stress in p-FinFETs with shorter channel length causes less NBTI issue,while the extra nitrogen passivation in the corner of bulk oxide induces less PBTI degradation as the channel length decreasing for n-FinFETs.The mechanism well matches the experimental result and provides one helpful guide for the improvement of reliability issues in the advanced FinFET process.展开更多
The key technologies for the dual high-k and dual metal gate, such as the electrical optimization of metal insert poly-Si stack structure, the separating of high-k and metal gate of n/pMOS in different regions of the ...The key technologies for the dual high-k and dual metal gate, such as the electrical optimization of metal insert poly-Si stack structure, the separating of high-k and metal gate of n/pMOS in different regions of the wafer, and the synchronous etching of n/pMOS gate stack, are successfully developed. First, reasonable flat-band voltage and equivalent oxide thickness of pMOS MIPS structure are obtained by further optimizing the HfSiAlON dielectric through incorporating more Al-O dipole at interface between HfSiAlON and bottom SiOx. Then, the separating of high-k and metal gate for n/pMOS is achieved by SC1（NH4OH：H2O2：H2O = 1 ： 1 ： 5） and DHF-based solution for the selective removing of n MOS TaN and Hf Si ON and by BCl3-based plasma and DHF-based solution for the selective removing of pMOS TaN/Mo and HfSiAlON.After that, the synchronous etching of n/pMOS gate stack is developed by utilizing optimized BCl3/SF6/O2/Ar plasma to obtain a vertical profile for TaN and TaN/Mo and by utilizing BCl3/Ar plasma combined with DHF-based solution to achieve high selectivity to Si substrate. Finally, good electrical characteristics of CMOS devices, obtained by utilizing these new developed technologies, further confirm that they are practicable technologies for DHDMG integration.展开更多
A detailed study of the magnetic characterizations of the top structure MgO/CoFeB/Mo is presented.The samples show strong perpendicular magnetic anisotropy（PMA） when the thickness of CoFeB is 0.9 nm and 1.1 nm.The s...A detailed study of the magnetic characterizations of the top structure MgO/CoFeB/Mo is presented.The samples show strong perpendicular magnetic anisotropy（PMA） when the thickness of CoFeB is 0.9 nm and 1.1 nm.The saturation magnetic moment and interface anisotropy constant are 1566 emu/cm3 and 3.75 erg/cm2,respectively.The magnetic dead layer（MDL） is about 0.23 nm in this system.Furthermore,strong capping layer thickness dependence is also observed.The strong PMA of 1.1 nm CoFeB only exists in a Mo cap layer thickness window of 1.2-2 nm.To maintain PMA,the metal layer could not be too thin or thick in these multilayers.The oxidation and diffusion of the metal capping layer should be respectively responsibility for the degradation of PMA in these thin or thick metal capping layer samples.展开更多
The multi-SCCO2 （supercritical carbon dioxide） release and dry process based on our specialized SCCO2 semiconductor process equipment is investigated and the releasing mechanism is discussed. The experiment results ...The multi-SCCO2 （supercritical carbon dioxide） release and dry process based on our specialized SCCO2 semiconductor process equipment is investigated and the releasing mechanism is discussed. The experiment results show that stuck cantilever beams were held up again under SCCO2 high pressure treatment and the repeatability of this process is nearly 100%.展开更多
Polarization optics plays a pivotal role in diffractive,refractive,and emerging flat optics,and has been widely employed in contemporary optical industries and daily life.Advanced polarization manipulation leads to ro...Polarization optics plays a pivotal role in diffractive,refractive,and emerging flat optics,and has been widely employed in contemporary optical industries and daily life.Advanced polarization manipulation leads to robust control of the polarization direction of light.Nevertheless,polarization control has been studied largely independent of the phase or intensity of light.Here,we propose and experimentally validate a Malus-metasurface-assisted paradigm to enable simultaneous and independent control of the intensity and phase properties of light simply by polarization modulation.The orientation degeneracy of the classical Malus’s law implies a new degree of freedom and enables us to establish a one-to-many mapping strategy for designing anisotropic plasmonic nanostructures to engineer the Pancharatnam–Berry phase profile,while keeping the continuous intensity modulation unchanged.The proposed Malus metadevice can thus generate a near-field greyscale pattern,and project an independent far-field holographic image using an ultrathin and single-sized metasurface.This concept opens up distinct dimensions for conventional polarization optics,which allows one to merge the functionality of phase manipulation into an amplitudemanipulation-assisted optical component to form a multifunctional nano-optical device without increasing the complexity of the nanostructures.It can empower advanced applications in information multiplexing and encryption,anti-counterfeiting,dual-channel display for virtual/augmented reality,and many other related fields.展开更多
The design of a conventional zoom lens is always challenging because it requires not only sophisticated optical design strategy, but also complex and precise mechanical structures for system adjustment. Here, we propo...The design of a conventional zoom lens is always challenging because it requires not only sophisticated optical design strategy, but also complex and precise mechanical structures for system adjustment. Here, we propose a continuous-zoom lens consisting of two chiral geometric metasurfaces with dielectric nanobrick arrays sitting on a transparent substrate. The metalens can continuously vary the focal length by rotating either of the two metasurfaces around its optical axis without changing any other conditions. Due to the polarization dependence of the geometric metasurface, the positive and negative polarities are interchangeable in one identical metalens only by changing the handedness of the incident circularly polarized light, which can generate varying focal lengths ranging from-∞ to +∞ in principle.展开更多
A substrate-ffee optical readout focal plane array （FPA） operating in 8-12 um with a heat sink structure （HSS） was fabricated and its performance was tested. The temperature distribution of the FPA with an HSS inv...A substrate-ffee optical readout focal plane array （FPA） operating in 8-12 um with a heat sink structure （HSS） was fabricated and its performance was tested. The temperature distribution of the FPA with an HSS investigated by using a commercial FLIR IR camera shows excellent uniformity. The thermal cross-talk effect existing in traditional substrate-free FPAs was eliminated effectively. The heat sink is fabricated successfully by electroplating copper, which provides high thermal capacity and high thermal conductivity, on the frame of substrate-free FPA. The FPA was tested in the optical-readout system, the results show that the response and NETD are 13.6 grey/K （F / # = 0.8） and 588 inK, respectively.展开更多
Multilevel ferroelectric field-effect transistors(FeFETs)integrated with HfO_(2)-based ferroelectric thin films demonstrate tremendous potential in high-speed massive data storage and neuromorphic computing applicatio...Multilevel ferroelectric field-effect transistors(FeFETs)integrated with HfO_(2)-based ferroelectric thin films demonstrate tremendous potential in high-speed massive data storage and neuromorphic computing applications.However,few works have focused on the stability of the multiple memory states in the HfO_(2)-based FeFETs.Here we firstly report the write/read disturb effects on the multiple memory states in the Hf_(0.5)Zr_(0.5)O_(2)(HZO)-based FeFETs.The multiple memory states in HZO-based FeFETs do not show obvious degradation with the write and read disturb cycles.Moreover,the retention characteristics of the intermediate memory states in HZO-based FeFETs with unsaturated ferroelectric polarizations are better than that of the memory state with saturated ferroelectric polarization.Through the deep analysis of the operation principle of in HZO-based FeFETs,we speculate that the better retention properties of intermediate memory states are determined by the less ferroelectric polarization degradation and the weaker ferroelectric polarization shielding.The experimental and theoretical evidences confirm that the long-term stability of the intermediate memory states in HZO-based FeFETs are as robust as that of the saturated memory state,laying a solid foundation for their practical applications.展开更多
基金Supported by the National Basic Research Program of China under Grant No 2011CBA00605the National Natural Science Foundation of China under Grant No 61404165
文摘Strained-Si0.73Ge0.27 channels are successfully integrated with high-R/metal gates in p-type metai-oxide- semi- conductor field effect transistors （pMOSFETs） using the replacement post-gate process. A silicon cap and oxide inter layers are inserted between Si0.73Ge0.27 and high-κ dielectric to improve the interface. The fab- ricated Si0.73Ge0.27 pMOSFETs with gate length of 3Onto exhibit good performance with high drive current （~428μA/μm at VDD = 1 V） and suppressed short-channel effects （DIBL^77mV/V and SS^90mV/decade）. It is found that the enhancement of effective hole mobility is up to 200% in long-gate-length Si0.73Ge0.27-channel pMOSFETs compared with the corresponding silicon transistors. The improvement of device performance is reduced due to strain relaxation as the gate length decreases, while 26% increase of the drive current is still obtained for 30-nm-gate-length Si0.73Ge0.27 devices.
基金the Beijing Municipal Natural Science Foundation,China(Grant No.4202078)the National Key Project of Science and Technology of China(Grant No.2017ZX02315001-002).
文摘A high crystalline quality of SiGe fin with an Si-rich composition area using the replacement fin processing is systematically demonstrated in this paper.The fin replacement process based on a standard FinFET process is developed.A width of less than 20-nm SiGe fin without obvious defect impact both in the direction across the fin and in the direction along the fin is verified by using the high angle annular dark field scanning transmission electron microscopy and the scanning moiréfringe imaging technique.Moreover,the SiGe composition is inhomogenous in the width of the fin.This is induced by the formation of 111 facets.Due to the atomic density of the 111 facets being higher,the epitaxial growth in the direction perpendicular to these facets is slower than in the direction perpendicular to 001.The Ge incorporation is then higher on the 111 facets than on the 001 facets.So,an Si-rich area is observed in the central area and on the bottom of SiGe fin.
基金Project supported by the Beijing Municipal Natural Science Foundation,China(Grant No.4202078).
文摘A narrowed Si_(0.7)Ge_(0.3)channel fin field-effect transistor(FinFET)device is demonstrated in detail by using an accuratecyclic wet treatment process.The Si_(0.7)Ge_(0.3)fin/per side of 0.63 nm in thickness can be accurately removed in each cycleby utilizing a self-limited oxidation with 40%HNO_(3)solution in 40 s and oxidation removal can be achieved with 1%HFsolution in 10 s.As a result,after the dummy gate removal,the fin width of Si_(0.7)Ge_(0.3)can be narrowed from 20 nm to 8 nmby utilizing 10 cycles of this wet treatment process.Compared with the conventional Si_(0.7)Ge_(0.3)FinFET under a similarprocess,the narrowed Si_(0.7)Ge_(0.3)channel FinFET can realize a strong gate control capability by using this newly developedwet treatment process,because its subthreshold slope can be reduced by 24%,improving from 87 mV/dec to 64 mV/dec.
文摘In vertical channel transistors(VCTs),source/drain ion implantation(I/I)represents a significant technical challenge due to inherent three-dimensional structural constraints,which induce complications such as difficulties in dummy gate forma-tion and shadowing effects of I/I.This article systematically investigates the impact of different implantation conditions on the performance of VCTs with and without dummy gates through TCAD simulation.It reveals the significant role of the lightly doped regions(LDRs)naturally formed due to ion implantation in source/drain of VCTs.Furthermore,it was found that VCT with-out dummy gates can achieve an approximately 27%increase in on-state current(Ion)under the same implantation conditions,and can greatly simplify the process flow and reduce costs.Finally,N-type and P-type VCTs were successfully fabricated using this implantation method.
基金financially supported by the National Natural Science Foundation of China (Nos.61874135,61904194 and 11905287)the National Major Project of Science and Technology of China (No.2017ZX02315001)+1 种基金the Youth Innovation Promotion Association,CAS (No.Y9YQ01R004)the Opening Project of Key Laboratory of Microelectronic Devices & Integrated Technology,Institute of Microelectronics,CAS (No.Y9YS05X002)。
文摘The n-type ultrathin fully depleted silicon-on-insulator(FDSOI) metal-oxide-semiconductor field-effect transistors(MOSFETs),with a Hf_(0.5)Zr_(0.5)O_(2) high dielectric permittivity(high-k) dielectric as gate insulator,were fabricated.The total ionizing dose effects were investigated,and an X-ray radiation dose up to 1500 krad(Si) was applied for both long-and short-channel devices.The short-channel devices(0.025-0.100 μm) exhibited less irradiation sensitivity compared with the long-channel devices(0.35-16 μm),leading to a 71% reduction in the irradiation-induced drain current growth and a 26% decrease in the shift of the threshold voltage.It was experimentally demonstrated that the OFF mode is the worst case among the three working conditions(OFF,ON and A110) for short-channel devices.Also,the determined effective electron mobility was enhanced by 38% after X-ray irradiation,attributed to the different compensations for charges triggered by radiation between the highk dielectric and buried oxide.By extracting the carrier mobility,gate length modulation,and source/drain(S/D)parasitic resistance,the degradation mechanism on X-ray irradiation was revealed.Finally,the split capacitance-voltage measurements were used to validate the analysis.
基金financially supported by the Strategic Pilot Project of the Chinese Academy of Sciences-Class A(No.XDA0330302)the National Natural Science Foundation of China(Nos.62374183 and 62304247)the 2021 Jilin Province Science and Technology Department Key R&D Projects(No.20210201031GX)。
文摘In order to effectively remove the residual Ge atoms at the surface of channel and improve the interfacial characteristic of gate-all-around(GAA)Si nanosheet field effect transistors,a low-temperature atomic-level trimming approach using ammonia peroxide water mixture(APM)solution treatment followed by diluted hydrofluoric acid is proposed and carried out.The capacitor samples with SiGe epitaxy layer,similar thermal budget and channel release process were fabricated using advanced high-k/metal-gate.An 83%reduction in surface roughness at atomic level is obtained by increasing APM treatment time.Moreover,there are 99.45% reduction in the interface state density(D_(it))and 96.8%leakage reduction in current density(J_(g))after APM treatment,indicating a promising method for future GAA NSFET performance optimization.
基金Supported by the National Basic Research Program of China under Grant No 2011CB921804the Beijing Key Subject Foundation of Condensed Matter Physics under Grant No 0114023
文摘The dependence of perpendicular magnetic anisotropy （PMA） on the barrier layer MgO thickness in MgO/CoFeB /Ta multilayers is investigated. The results show that the strongest PMA occurs in a small window of about 2 4nm with the increase of MgO thickness from 1-1Onto. The crystalline degree of MgO and the change of interatomic distance along the out-of-plane direction may be the main reasons for the change of PMA in these multilayers. Moreover, the roughnesses of 2- and 4-nm-thick MgO samples are 3.163 and 1.8 nm, respectively, and both the samples show PMA. These results could be used to tune the magnetic characteristic of the ultra thin CoFeB film for future applications in perpendicular magnetic devices.
基金the Science and Technology Program of Beijing Municipal Science and Technology Commission,China(Grant No.Z201100004220001)the National Major Project of Science and Technology of China(Grant No.2017ZX02315001)the Opening Project of Key Laboratory of Microelectronic Devices&Integrated Technology,Institute of Microelectronics,Chinese Academy of Sciences(Grant Nos.Y9YS05X002 and E0YS01X001).
文摘A comprehensive study of the negative and positive bias temperature instability(NBTI/PBTI)of 3D FinFET devices with different small channel lengths is presented.It is found while with the channel lengths shrinking from 100 nm to 30 nm,both the NBTI characteristics of p-FinFET and PBTI characteristics of n-FinFET turn better.Moreover,the channel length dependence on NBTI is more serious than that on PBTI.Through the analysis of the physical mechanism of BTI and the simulation of 3-D stress in the FinFET device,a physical mechanism of the channel length dependence on NBTI/PBTI is proposed.Both extra fluorine passivation in the corner of bulk oxide and stronger channel stress in p-FinFETs with shorter channel length causes less NBTI issue,while the extra nitrogen passivation in the corner of bulk oxide induces less PBTI degradation as the channel length decreasing for n-FinFETs.The mechanism well matches the experimental result and provides one helpful guide for the improvement of reliability issues in the advanced FinFET process.
基金Project supported by the National High Technology Research and Development Program of China(Grant No.2015AA010601)
文摘The key technologies for the dual high-k and dual metal gate, such as the electrical optimization of metal insert poly-Si stack structure, the separating of high-k and metal gate of n/pMOS in different regions of the wafer, and the synchronous etching of n/pMOS gate stack, are successfully developed. First, reasonable flat-band voltage and equivalent oxide thickness of pMOS MIPS structure are obtained by further optimizing the HfSiAlON dielectric through incorporating more Al-O dipole at interface between HfSiAlON and bottom SiOx. Then, the separating of high-k and metal gate for n/pMOS is achieved by SC1（NH4OH：H2O2：H2O = 1 ： 1 ： 5） and DHF-based solution for the selective removing of n MOS TaN and Hf Si ON and by BCl3-based plasma and DHF-based solution for the selective removing of pMOS TaN/Mo and HfSiAlON.After that, the synchronous etching of n/pMOS gate stack is developed by utilizing optimized BCl3/SF6/O2/Ar plasma to obtain a vertical profile for TaN and TaN/Mo and by utilizing BCl3/Ar plasma combined with DHF-based solution to achieve high selectivity to Si substrate. Finally, good electrical characteristics of CMOS devices, obtained by utilizing these new developed technologies, further confirm that they are practicable technologies for DHDMG integration.
基金Project supported by the National Fundamental Research Program of China(Grant No.2011CB921804)Beijing Key Subject Foundation of Condensed Matter Physics,China(Grant No.0114023)
文摘A detailed study of the magnetic characterizations of the top structure MgO/CoFeB/Mo is presented.The samples show strong perpendicular magnetic anisotropy（PMA） when the thickness of CoFeB is 0.9 nm and 1.1 nm.The saturation magnetic moment and interface anisotropy constant are 1566 emu/cm3 and 3.75 erg/cm2,respectively.The magnetic dead layer（MDL） is about 0.23 nm in this system.Furthermore,strong capping layer thickness dependence is also observed.The strong PMA of 1.1 nm CoFeB only exists in a Mo cap layer thickness window of 1.2-2 nm.To maintain PMA,the metal layer could not be too thin or thick in these multilayers.The oxidation and diffusion of the metal capping layer should be respectively responsibility for the degradation of PMA in these thin or thick metal capping layer samples.
基金Project supported by the National Natural Science Foundation of China(No.60976017)
文摘The multi-SCCO2 （supercritical carbon dioxide） release and dry process based on our specialized SCCO2 semiconductor process equipment is investigated and the releasing mechanism is discussed. The experiment results show that stuck cantilever beams were held up again under SCCO2 high pressure treatment and the repeatability of this process is nearly 100%.
基金the support from the MOST 2017YFA0205800the funding provided by the National Natural Science Foundation of China(Nos.91950110,11774273,11904267,61805184,and 11674256)+2 种基金the financial support from the Postdoctoral Innovation Talent Support Program of China(BX20180221)the China Postdoctoral Science Foundation(2019M652688)the financial support from the National Research Foundation,Prime Minister’s Office,Singapore under its Competitive Research Program(CRP award NRF CRP15-2015-03).
文摘Polarization optics plays a pivotal role in diffractive,refractive,and emerging flat optics,and has been widely employed in contemporary optical industries and daily life.Advanced polarization manipulation leads to robust control of the polarization direction of light.Nevertheless,polarization control has been studied largely independent of the phase or intensity of light.Here,we propose and experimentally validate a Malus-metasurface-assisted paradigm to enable simultaneous and independent control of the intensity and phase properties of light simply by polarization modulation.The orientation degeneracy of the classical Malus’s law implies a new degree of freedom and enables us to establish a one-to-many mapping strategy for designing anisotropic plasmonic nanostructures to engineer the Pancharatnam–Berry phase profile,while keeping the continuous intensity modulation unchanged.The proposed Malus metadevice can thus generate a near-field greyscale pattern,and project an independent far-field holographic image using an ultrathin and single-sized metasurface.This concept opens up distinct dimensions for conventional polarization optics,which allows one to merge the functionality of phase manipulation into an amplitudemanipulation-assisted optical component to form a multifunctional nano-optical device without increasing the complexity of the nanostructures.It can empower advanced applications in information multiplexing and encryption,anti-counterfeiting,dual-channel display for virtual/augmented reality,and many other related fields.
基金supported by the National Natural Science Foundation of China(Nos.11774273,11574240,61640409,and 61805184)the Outstanding Youth Funds of Hubei Province(No.2016CFA034)+2 种基金the Open Foundation of State Key Laboratory of Optical Communication Technologies and Networks,Wuhan Research Institute of Posts and Telecommunications(No.OCTN-201605)the Postdoctoral Innovation Talent Support Program of China(No.BX20180221)the Natural Science Foundation of Guangxi(No.2017GXNSFAA198048)
文摘The design of a conventional zoom lens is always challenging because it requires not only sophisticated optical design strategy, but also complex and precise mechanical structures for system adjustment. Here, we propose a continuous-zoom lens consisting of two chiral geometric metasurfaces with dielectric nanobrick arrays sitting on a transparent substrate. The metalens can continuously vary the focal length by rotating either of the two metasurfaces around its optical axis without changing any other conditions. Due to the polarization dependence of the geometric metasurface, the positive and negative polarities are interchangeable in one identical metalens only by changing the handedness of the incident circularly polarized light, which can generate varying focal lengths ranging from-∞ to +∞ in principle.
基金Project supported by the Chinese Academy of Sciences Knowledge Innovation Project(No.07YF031001)the Natural Science Foundation of Jiangsu Province,China(No.BK2012219),the Key Lab of Microelectronics Device and Integration Technology,China
文摘A substrate-ffee optical readout focal plane array （FPA） operating in 8-12 um with a heat sink structure （HSS） was fabricated and its performance was tested. The temperature distribution of the FPA with an HSS investigated by using a commercial FLIR IR camera shows excellent uniformity. The thermal cross-talk effect existing in traditional substrate-free FPAs was eliminated effectively. The heat sink is fabricated successfully by electroplating copper, which provides high thermal capacity and high thermal conductivity, on the frame of substrate-free FPA. The FPA was tested in the optical-readout system, the results show that the response and NETD are 13.6 grey/K （F / # = 0.8） and 588 inK, respectively.
基金This work was partly supported by the National Natural Science Foundation of China(Grant Nos.52122205,51902274,52072324,and 11932016)the Science and Technology Innovation Program of Hunan Province(Grant No.2020RC2077)the Natural Science Foundation of Hunan Province(Grant No.2019JJ50617).
文摘Multilevel ferroelectric field-effect transistors(FeFETs)integrated with HfO_(2)-based ferroelectric thin films demonstrate tremendous potential in high-speed massive data storage and neuromorphic computing applications.However,few works have focused on the stability of the multiple memory states in the HfO_(2)-based FeFETs.Here we firstly report the write/read disturb effects on the multiple memory states in the Hf_(0.5)Zr_(0.5)O_(2)(HZO)-based FeFETs.The multiple memory states in HZO-based FeFETs do not show obvious degradation with the write and read disturb cycles.Moreover,the retention characteristics of the intermediate memory states in HZO-based FeFETs with unsaturated ferroelectric polarizations are better than that of the memory state with saturated ferroelectric polarization.Through the deep analysis of the operation principle of in HZO-based FeFETs,we speculate that the better retention properties of intermediate memory states are determined by the less ferroelectric polarization degradation and the weaker ferroelectric polarization shielding.The experimental and theoretical evidences confirm that the long-term stability of the intermediate memory states in HZO-based FeFETs are as robust as that of the saturated memory state,laying a solid foundation for their practical applications.
