Fully differential cross sections （FDCS） are calculated within a four-body model for single ionization of helium by C6＋ impact at the incident energy of 100 MeV/a.u. （atomic unit）. The results are compared with e...Fully differential cross sections （FDCS） are calculated within a four-body model for single ionization of helium by C6＋ impact at the incident energy of 100 MeV/a.u. （atomic unit）. The results are compared with experimental data and other theoretical predictions. It is shown that our results are in very good agreement with experiment for three small momentum transfers in the scattering plane; however, some significant discrepancies are still present at the largest momentum transfer in both the scattering plane and the perpendicular plane. In actuality, the problem has not been explained by the theory during the last decade. Accordingly, the contributions of different scattering amplitudes to FDCS are analyzed. It is found that for the largest momentum transfer the cross section arising from a destructive interference of the three amplitudes is much smaller than the experimental data. However, the cross section due to the constructive interference of two scattering amplitudes between projectile-ionized electron interaction and projectile-passive electron interaction almost approaches the experimental data.展开更多
Several methods of characterization of trap levels like I-V, C-V and transient spectroscopy (DLTS) were used to determine the accurate values of the activation energies of traps present in N+P junctions obtained after...Several methods of characterization of trap levels like I-V, C-V and transient spectroscopy (DLTS) were used to determine the accurate values of the activation energies of traps present in N+P junctions obtained after retrograde profile implantation of indium and boron on silicon. Four main traps located at Ev + 0.15 eV, Ev + 0.21 eV, Ev + 0.28 eV and Ev + 0.46 eV are reported. Shallow levels are also calculated from I-V characteristics. Concurrently, indium channel doped NMOSFETs are investigated showing the kink phenomenon. In order to discuss the relationship between the kink effect and the active indium trap level situated at 0.16 eV, the transient effects are studied by varying the integration time and the temperature. The effects of substrate polarization are also carried out showing the reduction of the kink with the bulk positive polarization.展开更多
Fundamental quantum transport equation for impact-ionization processes in fusion plasmas is formulated in the actor-spectator description. The density-matrix formulism is adopted to treat both coherent and incoherent ...Fundamental quantum transport equation for impact-ionization processes in fusion plasmas is formulated in the actor-spectator description. The density-matrix formulism is adopted to treat both coherent and incoherent effects in a unified fashion. Quantum electrodynamic effects are also considered for high-temperature scenarios. Electron-impact ionization of uranium ion U91＋ and proton-impact ionization of hydrogen are given as examples.展开更多
针对标准体硅在CMOS和PD SOI CMOS两种工艺下的nMOSFETs,研究了沟道长度和宽度缩减对热载流子效应的影响。实验结果表明,在两种工艺下,热载流子的退化均随着沟道长度的减小而增强;然而,宽度的减小对两种工艺热载流子退化的影响却截然不...针对标准体硅在CMOS和PD SOI CMOS两种工艺下的nMOSFETs,研究了沟道长度和宽度缩减对热载流子效应的影响。实验结果表明,在两种工艺下,热载流子的退化均随着沟道长度的减小而增强;然而,宽度的减小对两种工艺热载流子退化的影响却截然不同:体硅工艺的热载流子退化随宽度的减小而增强,SOI工艺的热载流子退化随宽度的减小而减小。基于界面态对热载流子效应的影响深入分析了长度减小导致两种工艺下热载流子退化均加重的原因;同时基于边缘电场分布对热载流子效应的影响解释了宽度减小导致两种工艺下热载流子退化规律截然相反的现象。研究结果对于实际深亚微米工艺下,集成电路设计中器件工艺尺寸和版图结构的选择具有一定指导意义。展开更多
本文利用BBK模型和DWBA模型计算共面非对称几何条件下中、低能电子碰撞电离H原子的三重微分截面,所得结果与实验测量进行比较,进而研究初态入射电子的扭曲效应和末态出射电子之间的关联效应对三重微分截面的影响,并对这些影响给出定性...本文利用BBK模型和DWBA模型计算共面非对称几何条件下中、低能电子碰撞电离H原子的三重微分截面,所得结果与实验测量进行比较,进而研究初态入射电子的扭曲效应和末态出射电子之间的关联效应对三重微分截面的影响,并对这些影响给出定性的物理解释.我们发现,初态扭曲效应比较微弱,在150 e V以上入射能量时可以忽略;而末态关联效应则十分重要,它会抑制Binary峰的高度,改善Recoil峰的形状,并且使Binary峰和Recoil峰都向大角度偏移,从而使理论结果更接近实验测量.展开更多
考虑核间相互作用,利用修正的库仑玻恩(MCB-PT)模型计算了入射能量为16 Me V的O^(7+)碰撞氦单电离的全微分截面,并将计算结果与最近的实验数据和三体库仑波(3C)模型及连续扭曲波程函初态(CDW-EIS)模型所得结果进行了比较,发现MCB-PT理...考虑核间相互作用,利用修正的库仑玻恩(MCB-PT)模型计算了入射能量为16 Me V的O^(7+)碰撞氦单电离的全微分截面,并将计算结果与最近的实验数据和三体库仑波(3C)模型及连续扭曲波程函初态(CDW-EIS)模型所得结果进行了比较,发现MCB-PT理论结果在中间动量转移条件下binary峰的位置与实验结果符合得很好,且位于动量转移的方向上.此外,分析了扭曲效应对全微分截面的影响,表明随着动量转移的增加,扭曲效应更加明显.展开更多
The motion of current filaments in avalanching PIN diodes has been investigated in this paper by 2D transient numerical simulations. The simulation results show that the filament can move along the length of the PIN d...The motion of current filaments in avalanching PIN diodes has been investigated in this paper by 2D transient numerical simulations. The simulation results show that the filament can move along the length of the PIN diode back and forth when the self-heating effect is considered. The voltage waveform varies periodically due to the motion of the filament. The filament motion is driven by the temperature gradient in the filament due to the negative temperature dependence of the impact ionization rates. Contrary to the traditional understanding that current filamentation is a potential cause of thermal destruction, it is shown in this paper that the thermally-driven motion of current filaments leads to the homogenization of temperature in the diode and is expected to have a positive influence on the failure threshold of the PIN diode.展开更多
本文研究了0.8μm SOI NMOS晶体管,经剂量率为50rad(Si)/s的60Coγ射线辐照之后的总剂量效应,分析了器件在不同辐照条件和测量偏置下的辐照响应特性.研究结果表明:器件辐照时的栅偏置电压越高,辐照后栅氧化层中积累的空穴陷阱电荷越多,...本文研究了0.8μm SOI NMOS晶体管,经剂量率为50rad(Si)/s的60Coγ射线辐照之后的总剂量效应,分析了器件在不同辐照条件和测量偏置下的辐照响应特性.研究结果表明:器件辐照时的栅偏置电压越高,辐照后栅氧化层中积累的空穴陷阱电荷越多,引起的漏极泄漏电流越大.对于漏偏置为5V的器件,当栅电压大于阈值电压时,前栅ID-VG特性曲线中的漏极电流因碰撞电离而突然增大,体电极的电流曲线呈现倒立的钟形.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11274215)the Natural Science Foundation of Shanxi Province,China(Grants Nos.20051008 and 2010011009)the Technology Project of Shanxi Provincial Education Department,China(Grant No.20111011)
文摘Fully differential cross sections （FDCS） are calculated within a four-body model for single ionization of helium by C6＋ impact at the incident energy of 100 MeV/a.u. （atomic unit）. The results are compared with experimental data and other theoretical predictions. It is shown that our results are in very good agreement with experiment for three small momentum transfers in the scattering plane; however, some significant discrepancies are still present at the largest momentum transfer in both the scattering plane and the perpendicular plane. In actuality, the problem has not been explained by the theory during the last decade. Accordingly, the contributions of different scattering amplitudes to FDCS are analyzed. It is found that for the largest momentum transfer the cross section arising from a destructive interference of the three amplitudes is much smaller than the experimental data. However, the cross section due to the constructive interference of two scattering amplitudes between projectile-ionized electron interaction and projectile-passive electron interaction almost approaches the experimental data.
文摘Several methods of characterization of trap levels like I-V, C-V and transient spectroscopy (DLTS) were used to determine the accurate values of the activation energies of traps present in N+P junctions obtained after retrograde profile implantation of indium and boron on silicon. Four main traps located at Ev + 0.15 eV, Ev + 0.21 eV, Ev + 0.28 eV and Ev + 0.46 eV are reported. Shallow levels are also calculated from I-V characteristics. Concurrently, indium channel doped NMOSFETs are investigated showing the kink phenomenon. In order to discuss the relationship between the kink effect and the active indium trap level situated at 0.16 eV, the transient effects are studied by varying the integration time and the temperature. The effects of substrate polarization are also carried out showing the reduction of the kink with the bulk positive polarization.
文摘Fundamental quantum transport equation for impact-ionization processes in fusion plasmas is formulated in the actor-spectator description. The density-matrix formulism is adopted to treat both coherent and incoherent effects in a unified fashion. Quantum electrodynamic effects are also considered for high-temperature scenarios. Electron-impact ionization of uranium ion U91＋ and proton-impact ionization of hydrogen are given as examples.
文摘针对标准体硅在CMOS和PD SOI CMOS两种工艺下的nMOSFETs,研究了沟道长度和宽度缩减对热载流子效应的影响。实验结果表明,在两种工艺下,热载流子的退化均随着沟道长度的减小而增强;然而,宽度的减小对两种工艺热载流子退化的影响却截然不同:体硅工艺的热载流子退化随宽度的减小而增强,SOI工艺的热载流子退化随宽度的减小而减小。基于界面态对热载流子效应的影响深入分析了长度减小导致两种工艺下热载流子退化均加重的原因;同时基于边缘电场分布对热载流子效应的影响解释了宽度减小导致两种工艺下热载流子退化规律截然相反的现象。研究结果对于实际深亚微米工艺下,集成电路设计中器件工艺尺寸和版图结构的选择具有一定指导意义。
文摘本文利用BBK模型和DWBA模型计算共面非对称几何条件下中、低能电子碰撞电离H原子的三重微分截面,所得结果与实验测量进行比较,进而研究初态入射电子的扭曲效应和末态出射电子之间的关联效应对三重微分截面的影响,并对这些影响给出定性的物理解释.我们发现,初态扭曲效应比较微弱,在150 e V以上入射能量时可以忽略;而末态关联效应则十分重要,它会抑制Binary峰的高度,改善Recoil峰的形状,并且使Binary峰和Recoil峰都向大角度偏移,从而使理论结果更接近实验测量.
文摘考虑核间相互作用,利用修正的库仑玻恩(MCB-PT)模型计算了入射能量为16 Me V的O^(7+)碰撞氦单电离的全微分截面,并将计算结果与最近的实验数据和三体库仑波(3C)模型及连续扭曲波程函初态(CDW-EIS)模型所得结果进行了比较,发现MCB-PT理论结果在中间动量转移条件下binary峰的位置与实验结果符合得很好,且位于动量转移的方向上.此外,分析了扭曲效应对全微分截面的影响,表明随着动量转移的增加,扭曲效应更加明显.
基金Project supported by the National Natural Science Foundation of China(No.60776034)
文摘The motion of current filaments in avalanching PIN diodes has been investigated in this paper by 2D transient numerical simulations. The simulation results show that the filament can move along the length of the PIN diode back and forth when the self-heating effect is considered. The voltage waveform varies periodically due to the motion of the filament. The filament motion is driven by the temperature gradient in the filament due to the negative temperature dependence of the impact ionization rates. Contrary to the traditional understanding that current filamentation is a potential cause of thermal destruction, it is shown in this paper that the thermally-driven motion of current filaments leads to the homogenization of temperature in the diode and is expected to have a positive influence on the failure threshold of the PIN diode.
文摘本文研究了0.8μm SOI NMOS晶体管,经剂量率为50rad(Si)/s的60Coγ射线辐照之后的总剂量效应,分析了器件在不同辐照条件和测量偏置下的辐照响应特性.研究结果表明:器件辐照时的栅偏置电压越高,辐照后栅氧化层中积累的空穴陷阱电荷越多,引起的漏极泄漏电流越大.对于漏偏置为5V的器件,当栅电压大于阈值电压时,前栅ID-VG特性曲线中的漏极电流因碰撞电离而突然增大,体电极的电流曲线呈现倒立的钟形.
