提出了一个均匀、阶梯和线性掺杂漂移区SOI 高压器件的统一击穿模型. 基于分区求解二维Poisson方程,得到了不同漂移区杂质分布的横向电场和击穿电压的统一解析表达式. 借此模型并对阶梯数从0到无穷时器件结构参数对临界电场和击穿电压的影响进行了深入研究. 从理论上揭示了在厚膜SOI器件中用阶梯掺杂取代线性漂移区,不但可以保持较高的耐压,而且降低了设计和工艺难度. 解析结果、MEDICI仿真结果和实验结果符合良好.

An analytical transient turn-off current model for a type of the conductivity modulation power MOSFET transistors (CMT) with the extracted structure of the excess carrier is developed in the paper. With the non-quasi-static state (NQS) approximation for the excess carrier in the wide base of a low gain pnp transistor included in the CMT the three state equations of the charge, the voltage and the current are solved for the transient turn-off current analysis and ambipolar transport theory in high-level injection is used to evaluate the steady state current. Accounting for the perturbing effect of the carrier concentration redistribution under the condition of base width modulation and the coupling effect between the electron and hole current, the normalized transient current and turn-off time of the device with the extracted structure are obtained and compared with the experimental results.

提出了SOI基双级RESURF二维解析模型. 基于二维Poisson方程,获得了表面电势和电场分布解析表达式,给出了SOI的双级和单级RESURF条件统一判据,得到RESURF浓度优化区(DOR, doping optimal region),研究表明该判据和DOR还可用于其他单层或双层漂移区结构. 根据此模型,对双级RESURF结构的降场机理和击穿特性进行了研究,并利用二维器件仿真器MEDICI进行了数值仿真. 以此为指导成功研制了耐压为560V和720V的双级RESURF高压SOI LDMOS.解析解、数值解和实验结果吻合得较好.

An analytical breakdown model under on-state condition for high voltage RESURF LDMOS is proposed. The model considers the drift velocity saturation of carriers and influence of parasitic bipolar transistor. As a result, electric field profile of n-drift in LDMOS at on-state is obtained. Based on this model, the electric SOA of LDMOS can be determined. The analytical result s partially fit to our numerical ( by MEDICI) and experiment result s. This model is an aid to understand the device physics during on-state accurately and it also directs high voltage LDMOS design.

提出非均匀沟道MOS 辐照正空间电荷迁移率模型. 借助镜像法导出沟道电离杂质与辐照正空间电荷的二维场和二维互作用势的分布,由此给出非均匀n沟和p沟的迁移率表示式,其解析解与二维仿真值十分吻合.还借助二维仿真器计算均匀沟道MOS辐照正空间电荷迁移率的变化值,其值和文献[2,3]实验数据一致.