Novel SiC/Si heterojunction LDMOS with electric field modulation effect by reversed L-shaped field plate

Abstract

A novel SiC/Si heterojunction lateral double-diffused metal-oxidesemiconductor (LDMOS) with a reversed L-shaped field plate and a stepped oxide layer has been proposed to improve the tradeoff between the breakdown voltage (BV) and specific on-resistance (Ron,sp). The reversed L-shaped field plate is applied to modulate electric field distribution to make the breakdown occur in the low electric field area (SiC/Si interface), which increases the BV and decreases the Ron,sp of the device. Furthermore, a stepped oxide layer is used to cover the Si drift region and reshape the lateral electric field distribution by introducing a new electric field peak, which consequently enhances the BV. The simulated results have indicated that the BV of this proposed SiC/Si LDMOS increased from 226 V and 720 V to 992 V compared with the conventional Si LDMOS and SiC LDMOS, respectively, while maintaining a low Ron,sp of 27.62 mΩ·cm2.

Keywords

• Reversed L-shaped field plate
• Stepped oxide layer
• Breakdown voltage (BV)
• Specific on-resistance (Ron,Sp)
• Heterojunction LDMOS