Realization of High Voltage (> 700 V) in New SOI Devices With a Compound Buried Layer

A novel silicon-on-insulator (SOI) high-voltage device with a compound buried layer (CBL SOI) consisting of two oxide layers and a polysilicon layer between them is proposed. Its breakdown characteristic is investigated theoretically and experimentally. Theoretically, its vertical breakdown voltage (BV) is shared by two oxide layers; furthermore, the electric field in the lower buried oxide layer of E-I2 is increased from about 78 to 454 V/mu m by holes collected on the bottom interface of the polysilicon. Both result in an enhanced BV. Experimentally, 762-V SOT diode is obtained. The maximal temperature of CBL SOT diode is reduced by 16.9 K because a window in the upper buried oxide layer alleviates the self-heating effect.