SOI双槽隔离结构的耐压特性

Breakdown characteristic of SOI trench structure

理论推导了绝缘体上硅(SOI)双槽隔离结构的耐压模型.该模型表明,在SOI双槽隔离结构中,因隔离氧化层压降的不均衡,高压侧隔离氧化层提前发生介质击穿,从而导致SOI双槽隔离结构的临界击穿电压小于理论值.增大沟槽纵横比和减小槽间距可以减弱隔离氧化层上压降的不均衡性,提高SOI双槽隔离结构的临界击穿电压.Sentaurus器件仿真软件的模拟结果和华润上华半导体有限公司0.5μm 200 V SOI工艺平台下的流片测试结果均证明,减小槽间距和增大沟槽纵横比是提高双槽隔离结构临界击穿电压的有效方法,同时也证明了该耐压模型的正确性.

The breakdown model of double trench isolation structure on silicon on insulator （SOI） wafer is proposed. This model indicates that the imbalance of the voltage drop at isolation oxide lay- ers of the double trench isolation structure leads the isolation oxide layer near the high voltage regionto break down in advance, making the critical breakdown voltage less than the theoretical value. Furthermore, increasing the trench aspect ratio and decreasing the trench spacing can weaken the im- balance of the voltage drop and improve the critical breakdown voltage of the double trench isolationstructure on SOI wafer. The simulation results by Sentaurus device simulation software and the ex- periment results on CSMC 0.5 txm 200 V SO1 process platform from Central Semiconductor Manu- facturing Technologies Fabl Co. , Ltd. show that decreasing the trench spacing and increasing thetrench aspect ratio are the effective way to improve the critical breakdown voltage of the double trench isolation structure on SOI wafer. The results also prove the validity of the proposed model.