一种精确求解超薄栅NMOS器件隧穿电流的模型  

A Precise Model of Electron Tunneling Current Through Ultra-thin-oxide NMOS

作　　者：李宗林[1] 徐静平[1] 许胜国[1] 

机构地区：[1]华中科技大学电子科学与技术系,武汉430074

出　　处：《固体电子学研究与进展》2008年第2期162-166,共5页Research & Progress of SSE

基　　金：国家自然科学基金(60376019)资助项目

摘　　要：提出了一种精确求解隧穿电流的模型。通过自洽求解一维薛定谔方程和泊松方程,得到NMOS器件的半导体表面电势分布、反型层二维电子气的量子化能级以及对应的载流子浓度分布。为计算隧穿电流,采用了多步势垒逼近方法计算栅氧化物势垒层的隧穿几率,从而避免了WKB方法在突变边界处波函数不连续带来的缺陷。通过考虑(100)Si衬底的导带多能谷效应和栅极多晶硅耗尽效应,讨论了不同栅氧化层厚度下隧穿电流与栅压的依赖关系。模拟结果与实验数据吻合。A precise model of electron tunneling current through ultrathin-oxide NMOS is presented in this paper. Surface potential distribution, quantized energy levels and electron distribution of 2-D inversion electron gas are calculated by self-consistently solving the one-dimensional Schrodinger and Poisson equations. A multi-step potential approximation is used to calculate quantum mechanical transmission probability through the oxide barrier, which overcomes a problem that wave function is discontinuous at abrupt boundary in WKB approximation. Dependence of direct tunneling current on thickness of gate oxides is analyzed under various gate voltages by considering depletion effect in polysilicon and multiple-energy valley effect of conduction band in Si substrate. The simulation results are in a good agreement with experimental data.

关 键 词：N沟金属-氧化物-半导体器件 量子隧穿 反型层 超薄栅氧化物 

分 类 号：TN403[电子电信—微电子学与固体电子学]