Effects of p-type Islands Configuration on the Electrical Characteristics of the 4H-SiC Trench MOSFETs with Integrated Schottky Barrier Diode

Abstract

In this work, two types of trench gate MOSFETs embedded by Schottky Barrier Diode (SBD) are demonstrated by numerical simulations. The presented structures feature a p-type buried layer (BL) inside the drift region, leading to excellent balance between MOSFET and body diode characteristics of the device. Also, effects of p-buried layers position with respect to the gate and source trenches on the device's performances are revealed. The p-type islands embedded below the bottom of the trench regions (BLSI-MOS2) are found effective in shielding the contacts and reducing the leakage current even at high temperature of 225°C. Furthermore, the BL is short to source contacts or floating so as to justify the connection's effects on the dynamic characteristics. The results demonstrate that the reverse recovery charges <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${\left(Q_{\text{rr}}\right)}$</tex> of the BLSI-MOS2 can be reduced to approximately zero when BL is grounded, and the critical short-circuit energy can be increased compared to that of the structure with floating BL These results can provide guidance for design and modeling of4H-SiC SBD-integrated trench MOSFET.