LDD功率器件表面电场解析模型及优化

Analytical Model for Surface Electrical Field Distributions of LDD Power Devices

提出低掺杂漏(Lightly Doped Drain,LDD)功率器件表面电场和电势解析模型。基于分区求解二维Poisson方程,获得二维表面电场和电势的解析表达式。借助此模型,研究器件结构参数对表面电场和电势的影响;计算漂移区长度与击穿电压的关系,分析了击穿电压随低掺杂漏区掺杂浓度和漂移区厚度的变化,从理论上揭示了获得最大击穿电压的条件。解析结果与数值结果吻合较好,验证了模型的准确性,该模型可用于硅基LDD功率器件的设计优化。

An analytical model for surface electric field and potential distributions of LDD power devices is presented, Based on the 2-D Poisson＇s equation, the model gives closed form solutions of the surface potential and electric field distributions as a function of the structure parameters and drain bias; the dependence of breakdown voltage on drift region length is calculated. An effectual way to obtain optimum high-voltage devices is also proposed. Analytical results are in good agreement with results from MEDICI simulation, showing the validity of the model. This analytical model is a powerful tool to provide accurate first-order design schemes and physical insights into the bulksilicon LDD structure for device engineers.