Analytical and numerical studies of p+-emitters in silicon carbide bipolar devices
Analytical and numerical studies of p+-emitters in silicon carbide bipolar devices
复制标题
DOI：
10.1088/0268-1242/26/5/055024
复制
发表时间：
2011-05
影响因子：
1.9
通讯作者：
M. Levinshtein;T. T. Mnatsakanov-T.;A. Agarwal;J. Palmour
中科院分区：
文献类型：
--
作者：
M. Levinshtein;T. T. Mnatsakanov-T.;A. Agarwal;J. Palmour
在本文中，考虑了制造具有高注入系数的碳化硅p+发射极的方法。对提高发射极掺杂水平、消除劣化层、延长发射极电子寿命进行了讨论和分析。通过比较 Si 和 SiC p+–n 结，建立了 SiC 发射器的效率标准。结果表明，现代 SiC p+ 发射极的性能远未达到最佳状态。已经开发出分析模型来根据众所周知的“饱和电流”（jsn）方法来描述 SiC p+-n 结的特性，该方法考虑了控制高掺杂发射极层中传输现象的主要非线性效应：带隙变窄、俄歇复合、电子空穴散射、辐射复合和表面复合。结果表明，SiC p+–n 结的 jsn 值可能小至~2 × 10−49 A cm−2，即比现代 SiC 双极器件中 jsn 的最小值小两个数量级。分析了jsn 对电子寿命和发射极掺杂水平的依赖性。结果表明，p+发射极层中的电子寿命对器件的正向电压有很大影响。数值实验提供的数据证实了分析结果。
In this paper, ways to create silicon carbide p+-emitters with high injection coefficients are considered. Raising the emitter doping level, eliminating the deteriorated layer, and making longer the electron lifetime in the emitter are discussed and analyzed. The efficiency criteria are established for SiC emitters by comparing Si and SiC p+–n junctions. It is shown that the properties of modern SiC p+-emitters are far from being optimal. Analytical models have been developed to describe the properties of SiC p+–n junctions in terms of the well-known ‘saturation current’ (jsn) approach, which takes into account the main nonlinear effects that govern the transport phenomena in highly doped emitter layers: bandgap narrowing, Auger recombination, electron–hole scattering, radiative recombination, and surface recombination. It is demonstrated that the value of jsn for the SiC p+–n junction may be as small as ∼2 × 10−49 A cm−2, i.e. two orders of magnitude smaller than the smallest values of jsn in modern SiC bipolar devices. The dependences of jsn on the electron lifetime and doping level in the emitter are analyzed. It is shown that the electron lifetime in the p+-emitter layer has a vigorous effect on the device forward voltage. The analytical results are confirmed by the data furnished by numerical experiments.