Study on Novel Schottky Contact Super Barrier Rectifier with Deep Isolated MOS Trench in Epitaxial N-Drift Layer

Abstract

In this paper, a novel 120 V-class silicon Schottky contact super barrier rectifier with a deep isolated MOS trench in an epitaxial n-drift layer (DOT-SSBR) is studied through experiments, featuring the deep isolated MOS trenches (DOTs) in an epitaxial layer compared with conventional SSBR. The combination of SSBR and DOT obviously increase the breakdown voltage while preserving the significant advantages of SSBR. The pinching-off electric field effect by the DOTs in the epitaxial n-drift layer increases the average of electric field inside the drift layer and decreases the electric field on the mesa surface when the proposed DOT-SSBR is reversely biased. After the further optimization of the Schottky contact super barrier (SSB) parameters on mesa, the proposed DOT-SSBR maintains almost the same forward voltage, reduces the reverse leakage current at the reverse voltage of 50 V by approximately 10.0%, and greatly increases the breakdown voltage by approximately 38.6%, when compared with the conventional SSBR. The fabrication process, the measured high-temperature characteristics of forward I-V curves and reverse leakage current, and the measured reverse recovery current of the new device are also presented. An auxiliary simulation analysis to provide insight about the physics of the device is also presented.