The breakdown characteristics of a new SOI high voltage device with Sandwich Buried oxide layer

Abstract

A novel silicon-on-insulator (SOI) high voltage device structure is proposed. The structure is characterized by Sandwich Buried-Layer (SBL SOI) consisting of two oxide layers and a polysilicon layer between them. Its breakdown voltage (BV) is shared by two oxide buried layers, and the electric field in the lower buried oxide layer is increased from about 80V/µm of conventional SOI device to about 450V/µm due to the holes located on the bottom interface of the polysilicon. Both result in an enhancement of breakdown voltage. 822V SBL SOI diode is obtained in simulation. BV is increased by 32.6% compared with that of the conventional SOI diode in this paper. Moreover, charges collected on the bottom interface of the polysilicon shield the SOI layer and upper buried oxide layer from the back-gate bias effect for SBL SOI diode.