Threshold Voltage Degradation for n-Channel 4H-SiC Power MOSFETs

Esteban Guevara,Katherine Guerrero,Victor Herrera-Pérez,Cristian Rocha

doi:10.3390/jlpea10010003

Abstract

In this study, threshold voltage instability on commercial silicon carbide (SiC) power metal oxide semiconductor field electric transistor MOSFETs was evaluated using devices manufactured from two different manufacturers. The characterization process included PBTI (positive bias temperature instability) and pulsed IV measurements of devices to determine electrical parameters’ degradations. This work proposes an experimental procedure to characterize silicon carbide (SiC) power MOSFETs following two characterization methods: (1) Using the one spot drop down (OSDD) measurement technique to assess the threshold voltage explains temperature dependence when used on devices while they are subjected to high temperatures and different gate voltage stresses. (2) Measurement data processing to obtain hysteresis characteristics variation and the damage effect over threshold voltage. Finally, based on the results, it was concluded that trapping charge does not cause damage on commercial devices due to reduced value of recovery voltage, when a negative small voltage is applied over a long stress time. The motivation of this research was to estimate the impact and importance of the bias temperature instability for the application fields of SiC power n-MOSFETs. The importance of this study lies in the identification of the aforementioned behavior where SiC power n-MOSFETs work together with complementary MOS (CMOS) circuits.

Highlights

Silicon carbide (SiC) instead of silicon (Si) material is positioning itself as an alternative to manufactured MOSFETs, mainly by taking advantage of its high temperature operation stability, wide bandgap energy, high blocking voltage, ten times larger critical field, larger saturation velocity, and a greater thermal conductivity [1]
Power MOSFETs manufactured by silicon carbide (SiC) will have smaller drift zones to those manufactured in silicon, with identical voltage and on-resistance RON
This paper presented the study of PBTI of SiC MOSFETs with SiO2 and as the gate dielectric

Summary

Introduction

Silicon carbide (SiC) instead of silicon (Si) material is positioning itself as an alternative to manufactured MOSFETs, mainly by taking advantage of its high temperature operation stability, wide bandgap energy, high blocking voltage, ten times larger critical field, larger saturation velocity, and a greater thermal conductivity [1]. 4H-SiC is used to manufacture power MOSFETs and it is starting to become commercially available for power electronics applications [2]. Power MOSFETs manufactured by SiC will have smaller drift zones to those manufactured in silicon, with identical voltage and on-resistance RON. The used area can be reduced, allowing SiC MOSFETs to have one hundred times lower gate-source and gate drain capacitances [3,4]. SiC MOSFETs give significantly shortened dynamic and static losses, and they work at higher temperatures, higher power densities, and higher frequencies. 3. ExApeprrimacetincatallwParyocteodpurroedauncedsMtreesassuonreMmOenStFsETs suggests the application of high temperature gate bias (HTGB) where SiC power MOSFET degradation accelerates significantly.

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Figure Figure

Conclusions