A New High Voltage SOI Device with a Nonuniform Thickness Drift Region and Its Optimization
非均匀厚度漂移区SOI高压器件及其优化设计

A new SOI high-voltage device structure with nonuniform thickness drift region (n-uni SOI) and its optimization design method are proposed.Owing to the nonuniform thickness drift region,the electric field in the SOI layer is modulated and the electric field in the buried layer is enhanced,resulting in an enhancement of breakdown voltage.An analytical model taking the modulation effect into account is presented to optimize the device structure.Based on the analytical model,the dependencies of the electric field distribution and breakdown voltage on the device parameters are investigated.Numerical simulations support the analytical model.The breakdown voltage of the n-uni SOI LDMOS with n=3 is twice as high as that of a conventional SOI while its on-resistance maintains low.