变漂移区厚度SOI横向高压器件的优化设计

提出了一种耐压技术——横向变厚度VLT技术,以及基于此技术的一种高压器件结构——变厚度漂移区SOI横向高压器件,借助二维器件仿真器MEDICI,深入研究了该结构的耐压机理。结果表明,变厚度漂移区结构不但可以使横向击穿电压提高20%,纵向击穿电压提高10%,而且可以使漂移区掺杂浓度提高150%～200%,从而降低漂移区电阻,使器件优值提高40%以上。进一步研究表明,对于所研究的结构,采用一阶或二阶阶梯作为线性漂移区的近似,可以降低制造成本,并且不会导致器件性能的下降。

Optimization and Design of SOI Lateral High Voltage Devices with Varied Drift Region Thicknesses

Corresponding to the variation of lateral doping (VLD) technique, a sustaining-voltage technique-variation of lateral thickness (VLT) is developed in this paper. Based on the VLT technique, a new SOI high voltage device with step drift regions is proposed and investigated in detail using the two-dimensional semiconductor simulator MEDICI. The results show that the device with VLT structure is enabled to increase by 20% in lateral breakdown voltage, 10% in vertical breakdown voltage, and 150%～200% in doping concentrations in the drift region. As a result, the body resistance decreases and the Figure of Merit (FOM) increases beyond 40%. The devices with the single or two-step drift regions have the cost-effective merits due to the insensitivity of process conditions and the elimination of the high temperature annealing. At same time, the approximately ideal breakdown voltage and drift resistance are still maintained.