Numerical simulation of the effect of gold doping on the resistance to neutron irradiation of silicon diodes

We have carried out a numerical simulation of the effect of gold doping on the electrical characteristics of long silicon diodes exposed to neutron irradiation. The aim is to investigate the effect of gold on the hardness of the irradiated diodes. The reverse current voltage and capacitance voltage characteristics of doped and undoped diodes are calculated for different irradiation doses. The leakage current and the effective doping density are extracted from these two characteristics respectively. The hardness of the diodes is evaluated from the evolution of the leakage current and the effective doping density with irradiation doses. It was found that diodes doped with gold are less sensitive to irradiation than undoped ones. Thus gold appears to stabilise the electrical properties on irradiation. The conduction mechanism is studied by the evolution of the current with temperature. The evaluated activation energy indicates that as the gold doping or irradiation dose increases, the current switches from the basic diffusion to the generation-recombination process, and that it can even become ohmic for very high gold densities or irradiation doses.

SOI高压MOSFET的电流-电压特性模拟

在不同漂移区浓度分布下 ,通过二维数值模拟充分地研究了薄膜 SOI高压 MOSFET击穿电压的浓度相关性 ,指出了击穿优化对 MOSFET漂移区杂质浓度分布的要求。分析了MOSFET的电场电位分布随漏源电压的变化 ,提出寄生晶体管击穿有使 SOI MOSFET击穿降低的作用。

防止重掺砷CZ单晶硅组分过冷的探讨

在探讨组分过冷数学模型的基础上,针对重掺砷CZ单晶硅的生长,理论计算了防止组分过冷时固液界面处晶体温度梯度GS的临界值为51.32~33.10 K/cm.以此为依据,设计了具有较大温度梯度的18寸（60 cm）晶体生长热场,以数值模拟的方法,给出了固液界面处晶体的温度梯度GS的模拟值为54.68~38.14 K/cm.在晶体等径生长的各个阶段,固液界面处晶体的温度梯度GS的模拟值均在防止组分过冷的临界值之上,可以有效避免晶体生长过程中组分过冷的发生,并利用实际晶体生长试验的结果验证了以上分析的有效性.

选择性p型量子阱垒层掺杂在双波长发光二极管光谱调控中的作用

采用软件理论分析的方法对选择性p型掺杂量子阱垒层在InGaN双波长发光二极管(LED)中的光谱调控作用进行模拟分析.分析结果表明,选择性P型掺杂对量子阱中电子和空穴浓度分布的均衡性起到一定的调控作用,在适当选择p型掺杂量子阱垒层层数的条件下,能够改善量子阱中载流子的辐射复合速率,降低溢出电子浓度,从而有效提高芯片内量子效率,并减缓内量子效率随驱动电流增大而快速下降的趋势.随着活性层量子阱增加到特定数量,选择性P型掺杂的调控效果更加明显,LED芯片的双波长发光峰强度达到基本均衡.

基于非均匀掺杂的激光二极管抽运固体激光系统放大介质热特性分析

利用非均匀掺杂的设计思想,针对正面抽运、背面冷却的有源反射镜放大器结构中不同激活离子掺杂分布的介质进行了模拟计算,分析并比较了传统均匀掺杂介质与非均匀掺杂放大介质中的温度、温度梯度、应力、应变以及波前畸变的分布。结果表明,与传统均匀掺杂介质相比,非均匀掺杂放大介质内的温度、温度梯度、应力、应变与波前畸变均有明显的降低。模拟结果证明,非均匀掺杂可以改善有源反射镜放大器构型冷却与产热异面的问题,可以有效地提高放大器增益介质热管理性能,为进一步讨论基于非均匀掺杂的放大介质的热管理优化提供了基础。