A Ultra-Low Specific On-Resistance and Extended Gate SJ LDMOS Structure

Abstract

A new structure of extended gate (EG) SJ LDMOS is proposed in this paper to overcome the substrate assisted depletion (SAD) effect in the structure of Super-Junction lateral double diffused metal oxide semiconductor (SJ LDMOS). Different from other surface SJ structures, the SJ layer of the structure is located in the body of the drift region. Gate oxide and silicon layer form the EG Structure-Oxide-Semiconductor structure that is similar to Metal–Insulator–Semiconductor capacitor. The the N-drift of the EG structure can obtain the charge compensation to overcome the SAD effect, and a nearly rectangular electric field is achieved. In the on-state, the EG structure has two conductive channels and the accumulation layer is formed on the drift region. By accumulating high concentration electrons in the channels, the specific on-resistance (RON,sp) is greatly reduced. When the drift length is 24 μm, 431.4 V breakdown voltage (VB) and 9.8 mΩ cm2 RON,sp are achieved, and the figure of merit is 18.9 MW cm−2.