Analysis of radiation effect of a novel SOI-Like LDMOS structure

Abstract

This study proposes a new SL LDMOS structure similar to a silicon-on-insulator. The P+/N structure is used to replace the buried oxygen layer of traditional SOI LDMOS devices. The N-type layer is made of SiC material, and the highly doped P-type layer is used to partially deplete the SiC layer to achieve the SOI Like effect. At the same time, the highly doped buried layer is formed by ion implantation in the SiC layer to adjust the electric field in the drift region and improve the breakdown voltage. The Silvaco TCAD software is used to conduct a two-dimensional simulation of the proposed structure. The breakdown voltage of the device is 306 V. Compared with the SOI LDMOS under the same withstand voltage, the proposed SL LDMOS has about 32.9% lower the on-resistance and better electrical characteristics. In the study of radiation effects, the burnout threshold of the proposed structure is LET = 0.93 pC/μm and Vd = 222 V, which shows that the device has good anti-single event burnout performance. In the study of the total-ionizing-dose, when the total dose is higher than 119 Krad(Si), the breakdown voltage of the proposed device is significantly higher than that of the SOI LDMOS device. This can effectively address the shortcomings of SOI LDMOS devices regarding the total-ionizing-dose. Therefore, the proposed structure is suitable for application in harsh environments such as those with high radiation.