新型非均匀沟道掺杂恒流二极管结构及输出特性研究

Structure and output characteristics of novel nonuniform channel doped current regulative diode

依据电参数指标和实测的输出特性曲线,利用Silvaco-TCAD半导体器件仿真软件对水平沟道恒流二极管输出特性和结构参数进行研究。为了改善常规恒流二极管的恒流值(I_(H))、夹断电压(V_(P))、阻断电压(V_(R))、恒流值高低温变化率对沟道结构参数要求的矛盾关系,提出了一种新型的非均匀沟道掺杂的恒流二极管器件结构,并对新型结构的沟道结构参数进行了优化。研究表明:对于常规恒流二极管,采用掺杂浓度较高且宽度较窄的沟道结构,虽然有利于降低恒流二极管恒流值高低温变化率,但器件阻断电压很难满足指标要求。提出的新型非均匀掺杂沟道结构能够优化沟道内及沟道边缘电场分布,较低的沟道顶部掺杂浓度降低了沟道顶部峰值电场强度,显著增大了恒流二极管阻断电压。在较窄沟道条件下,较高的沟道底部掺杂浓度使得恒流值满足指标要求,并显著降低了恒流值高低温变化率。

According to the electrical parameters and measured output characteristic curves,the output characteristics and structural parameters of the horizontal channel current regulative diode were studied by using Silvaco-TCAD semiconductor device simulation software.In order to solve the contradiction between the constant current value(I_(H)),clipping voltage(V_(P)),blocking voltage(V_(R))and the change rate of high and low temperature of constant current value on the channel structure parameters of conventional current regulative diode,a novel current regulative diode with non-uniform doped channel was proposed,and the channel structure parameters of the new current regulative diode were optimized.The results show that although the channel structure with high doping concentration and narrow width is beneficial to reduce the high and low temperature variation rate of the constant current value of the current regulative diode,the blocking voltage of the device is difficult to meet the requirements of the index for the conventional current regulative diode.The proposed non-uniform doping channel structure can optimize the electric field distribution in and at the edge of the channel.Meanwhile,the lower doping concentration at the top of the channel can reduce the peak electric field intensity and increase the blocking voltage of the current regulative diode significantly.Under the narrow channel condition,increasing doping concentration at the bottom of the channel makes the constant current value meet the requirement of the index and reduces the high and low temperature variation rate of the constant current value significantly.