3200V双p阱终端VDMOS击穿特性仿真研究

Simulation Research on Breakdown Characteristics of 3200V VDMOS with Double p-Well Termination

摘要:

基于场限环终端技术理论,提出了一种具有双p阱结构的垂直双扩散金属氧化物半导体场效应晶体管(VDMOS)。通过数值模拟软件分别仿真了p阱各项参数和漂移区掺杂浓度与击穿电压的关系,提取器件击穿时的表面电场并分析其击穿机理。研究结果表明,当漂移区掺杂浓度一定时,击穿电压随p阱数量和结深的增大而增大,随p阱掺杂浓度的增大而先增大后减小；当p阱参数一定时,击穿电压随漂移区掺杂浓度的增大而先增大后减小。经优化器件各项参数,击穿电压(VB)达到3200V,与传统平面栅型VDMOS相比提升了305%,终端有效长度仅为26μm,表面电场最大值为1.21×10⁶V/cm,且分布相对均匀,终端稳定性和可靠性高。

Abstract:

A vertical double-diffused metal oxide semiconductor (VDMOS) with double p-well structure was proposed based on the theory of field limiting ring termination technology. The relations of the breakdown voltage with the parameters of the p-well and doping concentration of the drift region were simulated by numerical simulation software. The surface electric field was extracted when the device was struck and the breakdown principle was analyzed. The results show that when the doping concentration of the drift region is constant, the breakdown voltage increases with the increase of number and junction depth of the p-well, and first increases and then decreases with the p-well doping concentration. When the parameters of the p-well are constant, the breakdown voltage increases first and then decreases with the increase of doping concentration of the drift region. After optimizing the device parameters, the breakdown voltage (VB) of the device reaches 3200V, which is 305% higher than that of the traditional planar-gate VDMOS. The effective length of the termination is only 26μm, with the maximum value of surface electric field of 1.21×10⁶V/cm. The distribution of the surface electric field is relatively uniform, which results in high stability and reliability of the termination.