The N2-plasma treatment on a HfO2 blocking layer of Au nanocrystal nonvolatile memory without any post annealing is investigated. The electrical characteristics of the MOS capacitor with structure of Al–Ta N/HfO2/Si ...The N2-plasma treatment on a HfO2 blocking layer of Au nanocrystal nonvolatile memory without any post annealing is investigated. The electrical characteristics of the MOS capacitor with structure of Al–Ta N/HfO2/Si O2/p-Si are also characterized. After N2-plasma treatment, the nitrogen atoms are incorporated into HfO2 film and may passivate the oxygen vacancy states. The surface roughness of HfO2 film can also be reduced. Those improvements of HfO2 film lead to a smaller hysteresis and lower leakage current density of the MOS capacitor. The N2-plasma is introduced into Au nanocrystal（NC） nonvolatile memory to treat the HfO2 blocking layer. For the N2-plasma treated device, it shows a better retention characteristic and is twice as large in the memory window than that for the no N2-plasma treated device. It can be concluded that the N2-plasma treatment method can be applied to future nonvolatile memory applications.展开更多
This paper discusses the effect of N2 plasma treatment before dielectric deposition on the electrical performance of a Al203/AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor （MISHEMT）,with A...This paper discusses the effect of N2 plasma treatment before dielectric deposition on the electrical performance of a Al203/AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor （MISHEMT）,with Al203 deposited by atomic layer deposition.The results indicated that the gate leakage was decreased two orders of magnitude after the Al203/AlGaN interface was pretreated by N2 plasma.Furthermore,effects of N2 plasma pretreatrnent on the electrical properties of the AlGaN/Al2O3 interface were investigated by x-ray photoelectron spectroscopy measurements and the interface quality between Al203 and AlGaN film was improved.展开更多
为提升瓦斯抽采利用率、促进煤矿安全生产,采用介质阻挡放电(DBD)试验系统对CH4-O2-N2-H2O反应体系进行低温等离子体转化研究,分析水蒸气与CH4物质的量比、O2/N2物质的量比、放电电压、放电频率,以及气体总流量对CH4转化率及主要产物产...为提升瓦斯抽采利用率、促进煤矿安全生产,采用介质阻挡放电(DBD)试验系统对CH4-O2-N2-H2O反应体系进行低温等离子体转化研究,分析水蒸气与CH4物质的量比、O2/N2物质的量比、放电电压、放电频率,以及气体总流量对CH4转化率及主要产物产率的影响。结果表明:CH4-O2-N2-H2O反应体系DBD的主要产物为H2、CO、CO2、C2H2、C2H4、C2H6和CH3OH;反应参数对CH4转化率和H2、CO、CO2、C2H6、CH3OH产率影响较为显著,而对C2H2、C2H4产率影响不显著;CH4转化率及主要产物产率均在放电频率为9.8 k Hz时取得最大值。展开更多
Driven by pulse modulated radio-frequency plasma in capacitively coupled discharge are studied by source, the behavior of SiH4/N2/02 using a one-dimensional fluid model. Totally, 48 different species （electrons, ions...Driven by pulse modulated radio-frequency plasma in capacitively coupled discharge are studied by source, the behavior of SiH4/N2/02 using a one-dimensional fluid model. Totally, 48 different species （electrons, ions, neutrals, radicals and excited species） are involved in this simulation. Time evolution of the particle densities and electron temperature with different duty cycles are obtained, as well as the electronegativity nsiH-3 /ne of the main negative ion （Sill3 ）. The results show that, by reducing the duty cycle, higher electron temperature and particle density can be achieved for the same average dissipated power, and the ion energy can also be effectively reduced, which will offer evident improvement in plasma deposition processes compared with the case of continuous wave discharge.展开更多
A two-dimensional （2D） fluid model is presented to study the behavior of silicon plasma mixed with SiH4 , N2 , and NH3 in a radio-frequency capacitively coupled plasma （CCP） reactor. The plasma–wall interaction ...A two-dimensional （2D） fluid model is presented to study the behavior of silicon plasma mixed with SiH4 , N2 , and NH3 in a radio-frequency capacitively coupled plasma （CCP） reactor. The plasma–wall interaction （including the deposition） is modeled by using surface reaction coefficients. In the present paper we try to identify, by numerical simulations, the effect of variations of the process parameters on the plasma properties. It is found from our simulations that by increasing the gas pressure and the discharge gap, the electron density profile shape changes continuously from an edge-high to a center-high, thus the thin films become more uniform. Moreover, as the N2 /NH3 ratio increases from 6/13 to 10/9, the hydrogen content can be significantly decreased, without decreasing the electron density significantly.展开更多
It is known that gas flow rate is a key factor in controlling industrial plasma processing. In this paper, a 2D PIC/MCC model is developed for an rf hollow cathode discharge with an axial nitrogen gas flow. The effect...It is known that gas flow rate is a key factor in controlling industrial plasma processing. In this paper, a 2D PIC/MCC model is developed for an rf hollow cathode discharge with an axial nitrogen gas flow. The effects of the gas flow rate on the plasma parameters are calculated and the results show that： with an increasing flow rate, the total ion（N＋2, N＋） density decreases, the mean sheath thickness becomes wider, the radial electric field in the sheath and the axial electric field show an increase, and the energies of both kinds of nitrogen ions increase;and, as the axial ion current density that is moving toward the ground electrode increases, the ion current density near the ground electrode increases. The simulation results will provide a useful reference for plasma jet technology involving rf hollow cathode discharges in N2.展开更多
Planar radio frequency inductively coupled plasmas（ICP） are employed for low-voltage ion implantation processes,with capacitive pulse biasing of the substrate for modulation of the ion energy. In this work, a two-di...Planar radio frequency inductively coupled plasmas（ICP） are employed for low-voltage ion implantation processes,with capacitive pulse biasing of the substrate for modulation of the ion energy. In this work, a two-dimensional（2D） selfconsistent fluid model has been employed to investigate the influence of the pulsed bias power on the nitrogen plasmas for various bias voltages and pulse frequencies. The results indicate that the plasma density as well as the inductive power density increase significantly when the bias voltage varies from 0 V to-4000 V, due to the heating of the capacitive field caused by the bias power. The N＋fraction increases rapidly to a maximum at the beginning of the power-on time, and then it decreases and reaches the steady state at the end of the glow period. Moreover, it increases with the bias voltage during the power-on time, whereas the N2-＋ fraction exhibits a reverse behavior. When the pulse frequency increases to 25 kHz and40 kHz, the plasma steady state cannot be obtained, and a rapid decrease of the ion density at the substrate surface at the beginning of the glow period is observed.展开更多
A hybrid PIC/MC model is developed in this work for H2-xN2 capacitively coupled radio-frequency （CCRF） discharges in which we take into account 43 kinds of collisions reaction processes between charged particles （e...A hybrid PIC/MC model is developed in this work for H2-xN2 capacitively coupled radio-frequency （CCRF） discharges in which we take into account 43 kinds of collisions reaction processes between charged particles （e-, H3＋, H＋, H＋, N＋, N＋） and ground-state molecules （H2, H＋ N2）. In addition, the mean energies and densities of electrons and ions （ 3, H＋, H＋）, and electric field distributions in the H2-N2 CCRF discharge are simulated by this model. Furthermore, the effects of addition of a variable percentage of nitrogen （0-30%） into the H2 discharge on the plasma processes and discharge characteristics are studied. It is shown that by increasing the percentage of nitrogen added to the system, the RF sheath thickness will narrow, the sheath electric field will be enhanced, and the mean energy of hydrogen ions impacting the electrodes will be increased. Because the electron impact ionization and dissociative ionization rates increase when N2 is added to the system, the electron mean density will increase while the electron mean energy and hydrogen ion density near the electrodes will decrease. This work aims to provide a theoretical basis for experimental studies and technological developments with regard to H2-N2 CCRF plasmas.展开更多
Carbon nanosheet films were deposited on A1 substrates by using plasma assisted chemical vapor deposition （PACVD） technique. And after being peeled off from A1 substrates, carbon nanosheet powders （CNSPs） were obt...Carbon nanosheet films were deposited on A1 substrates by using plasma assisted chemical vapor deposition （PACVD） technique. And after being peeled off from A1 substrates, carbon nanosheet powders （CNSPs） were obtained. In Raman spectrum of carbon film, there was a strong and broadened peak at about 1,580 cm^-1, indicating a carbon diamond-like film. Atomic force microscope image showed that the carbon diamond-like film had a grain size less than 100 nm, and its surface roughness Ra was 17.95 nm in an area of 5×5 μm^2. The CNSPs were irregular sheets with curly edges and a length of several micrometers to several hundreds of micrometers. The BET surface area of CNSPs was 6.66 m^2/g with no micro-pore present, which was confirmed by N2 adsorption-desorption characterization. In the adsorption testing, when the relative pressure p/po was higher than 0.3, the adsorption behavior did not follow the Langmuir equation. The addition of CNSPs to carbon black （catalyst support） could improve hydrodesulfurization performance of carbon supported Ni-W catalysts for diesel oil.展开更多
基金supported by the High Level Talent Project of Xiamen University of Technology,China(Grant Nos.YKJ16012R and YKJ16016R)the National Natural Science Foundation of China(Grant No.51702271)
文摘The N2-plasma treatment on a HfO2 blocking layer of Au nanocrystal nonvolatile memory without any post annealing is investigated. The electrical characteristics of the MOS capacitor with structure of Al–Ta N/HfO2/Si O2/p-Si are also characterized. After N2-plasma treatment, the nitrogen atoms are incorporated into HfO2 film and may passivate the oxygen vacancy states. The surface roughness of HfO2 film can also be reduced. Those improvements of HfO2 film lead to a smaller hysteresis and lower leakage current density of the MOS capacitor. The N2-plasma is introduced into Au nanocrystal（NC） nonvolatile memory to treat the HfO2 blocking layer. For the N2-plasma treated device, it shows a better retention characteristic and is twice as large in the memory window than that for the no N2-plasma treated device. It can be concluded that the N2-plasma treatment method can be applied to future nonvolatile memory applications.
基金Project supported by National Advanced Research Program (Grant No 51308030102)Xi’an Applied Materials Innovation Fund (Grant No XA-AM-200616)National Natural Science Foundation of China (Grant Nos 60506020 and 60676048)
文摘This paper discusses the effect of N2 plasma treatment before dielectric deposition on the electrical performance of a Al203/AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor （MISHEMT）,with Al203 deposited by atomic layer deposition.The results indicated that the gate leakage was decreased two orders of magnitude after the Al203/AlGaN interface was pretreated by N2 plasma.Furthermore,effects of N2 plasma pretreatrnent on the electrical properties of the AlGaN/Al2O3 interface were investigated by x-ray photoelectron spectroscopy measurements and the interface quality between Al203 and AlGaN film was improved.
文摘为提升瓦斯抽采利用率、促进煤矿安全生产,采用介质阻挡放电(DBD)试验系统对CH4-O2-N2-H2O反应体系进行低温等离子体转化研究,分析水蒸气与CH4物质的量比、O2/N2物质的量比、放电电压、放电频率,以及气体总流量对CH4转化率及主要产物产率的影响。结果表明:CH4-O2-N2-H2O反应体系DBD的主要产物为H2、CO、CO2、C2H2、C2H4、C2H6和CH3OH;反应参数对CH4转化率和H2、CO、CO2、C2H6、CH3OH产率影响较为显著,而对C2H2、C2H4产率影响不显著;CH4转化率及主要产物产率均在放电频率为9.8 k Hz时取得最大值。
基金supported by National Natural Science Foundation of China (No.10775025)Important National Science & Technology Specific Project of China (No.2011ZX02403-001)Program for New Century Excellent Talents in University of China (NCET-08-0073)
文摘Driven by pulse modulated radio-frequency plasma in capacitively coupled discharge are studied by source, the behavior of SiH4/N2/02 using a one-dimensional fluid model. Totally, 48 different species （electrons, ions, neutrals, radicals and excited species） are involved in this simulation. Time evolution of the particle densities and electron temperature with different duty cycles are obtained, as well as the electronegativity nsiH-3 /ne of the main negative ion （Sill3 ）. The results show that, by reducing the duty cycle, higher electron temperature and particle density can be achieved for the same average dissipated power, and the ion energy can also be effectively reduced, which will offer evident improvement in plasma deposition processes compared with the case of continuous wave discharge.
基金Project supported by the China Postdoctoral Science Foundation (Grant No. 2012M511603)the National Natural Science Foundation of China (Grant Nos. 11105057 and 10775025)+1 种基金the Natural Science Foundation of Hubei Province of China (Grant No. 2007ABA035)the Program for New Century Excellent Talents in University of China (Grant No. NCET-08-0073)
文摘A two-dimensional （2D） fluid model is presented to study the behavior of silicon plasma mixed with SiH4 , N2 , and NH3 in a radio-frequency capacitively coupled plasma （CCP） reactor. The plasma–wall interaction （including the deposition） is modeled by using surface reaction coefficients. In the present paper we try to identify, by numerical simulations, the effect of variations of the process parameters on the plasma properties. It is found from our simulations that by increasing the gas pressure and the discharge gap, the electron density profile shape changes continuously from an edge-high to a center-high, thus the thin films become more uniform. Moreover, as the N2 /NH3 ratio increases from 6/13 to 10/9, the hydrogen content can be significantly decreased, without decreasing the electron density significantly.
基金supported by the Natural Science Foundation of Hebei Province,China(No.A2012205072)
文摘It is known that gas flow rate is a key factor in controlling industrial plasma processing. In this paper, a 2D PIC/MCC model is developed for an rf hollow cathode discharge with an axial nitrogen gas flow. The effects of the gas flow rate on the plasma parameters are calculated and the results show that： with an increasing flow rate, the total ion（N＋2, N＋） density decreases, the mean sheath thickness becomes wider, the radial electric field in the sheath and the axial electric field show an increase, and the energies of both kinds of nitrogen ions increase;and, as the axial ion current density that is moving toward the ground electrode increases, the ion current density near the ground electrode increases. The simulation results will provide a useful reference for plasma jet technology involving rf hollow cathode discharges in N2.
基金supported by the National Natural Science Foundation of China(Grant Nos.11175034,11335004,and 11405019)the Important National Science and Technology Specific Project of China(Grant No.2011 ZX 02403-001)
文摘Planar radio frequency inductively coupled plasmas（ICP） are employed for low-voltage ion implantation processes,with capacitive pulse biasing of the substrate for modulation of the ion energy. In this work, a two-dimensional（2D） selfconsistent fluid model has been employed to investigate the influence of the pulsed bias power on the nitrogen plasmas for various bias voltages and pulse frequencies. The results indicate that the plasma density as well as the inductive power density increase significantly when the bias voltage varies from 0 V to-4000 V, due to the heating of the capacitive field caused by the bias power. The N＋fraction increases rapidly to a maximum at the beginning of the power-on time, and then it decreases and reaches the steady state at the end of the glow period. Moreover, it increases with the bias voltage during the power-on time, whereas the N2-＋ fraction exhibits a reverse behavior. When the pulse frequency increases to 25 kHz and40 kHz, the plasma steady state cannot be obtained, and a rapid decrease of the ion density at the substrate surface at the beginning of the glow period is observed.
基金supported by the Natural Science Foundation of Hebei Province,China(No.A2012205072)
文摘A hybrid PIC/MC model is developed in this work for H2-xN2 capacitively coupled radio-frequency （CCRF） discharges in which we take into account 43 kinds of collisions reaction processes between charged particles （e-, H3＋, H＋, H＋, N＋, N＋） and ground-state molecules （H2, H＋ N2）. In addition, the mean energies and densities of electrons and ions （ 3, H＋, H＋）, and electric field distributions in the H2-N2 CCRF discharge are simulated by this model. Furthermore, the effects of addition of a variable percentage of nitrogen （0-30%） into the H2 discharge on the plasma processes and discharge characteristics are studied. It is shown that by increasing the percentage of nitrogen added to the system, the RF sheath thickness will narrow, the sheath electric field will be enhanced, and the mean energy of hydrogen ions impacting the electrodes will be increased. Because the electron impact ionization and dissociative ionization rates increase when N2 is added to the system, the electron mean density will increase while the electron mean energy and hydrogen ion density near the electrodes will decrease. This work aims to provide a theoretical basis for experimental studies and technological developments with regard to H2-N2 CCRF plasmas.
基金the Venture Fund of PetroChina Company Limted (050511-3-4)
文摘Carbon nanosheet films were deposited on A1 substrates by using plasma assisted chemical vapor deposition （PACVD） technique. And after being peeled off from A1 substrates, carbon nanosheet powders （CNSPs） were obtained. In Raman spectrum of carbon film, there was a strong and broadened peak at about 1,580 cm^-1, indicating a carbon diamond-like film. Atomic force microscope image showed that the carbon diamond-like film had a grain size less than 100 nm, and its surface roughness Ra was 17.95 nm in an area of 5×5 μm^2. The CNSPs were irregular sheets with curly edges and a length of several micrometers to several hundreds of micrometers. The BET surface area of CNSPs was 6.66 m^2/g with no micro-pore present, which was confirmed by N2 adsorption-desorption characterization. In the adsorption testing, when the relative pressure p/po was higher than 0.3, the adsorption behavior did not follow the Langmuir equation. The addition of CNSPs to carbon black （catalyst support） could improve hydrodesulfurization performance of carbon supported Ni-W catalysts for diesel oil.
