Electrically Active Defects in SiC Power MOSFETs

Abstract

The performance and reliability of the state-of-the-art power 4H-SiC metal–oxide–semiconductor field-effect transistors (MOSFETs) are affected by electrically active defects at and near the interface between SiC and the gate dielectric. Specifically, these defects impact the channel-carrier mobility and threshold voltage of SiC MOSFETs, depending on their physical location and energy levels. To characterize these defects, techniques have evolved from those used for Si devices to techniques exclusively designed for the SiC MOS structure and SiC MOSFETs. This paper reviews the electrically active defects at and near the interface between SiC and the gate dielectric in SiC power MOSFETs and MOS capacitors. First, the defects are classified according to their physical locations and energy positions into (1) interface traps, (2) near interface traps with energy levels aligned to the energy gap, and (3) near-interface traps with energy levels aligned to the conduction band of SiC. Then, representative published results are shown and discussed for each class of defect.

High Performance Pd/4H-SiC Epitaxial Schottky Barrier Radiation Detectors for Harsh Environment Applications

“…The Ti impurity appears from the Ti crucible used in the growth process and is known to appear in as-grown SiC [ 43 , 44 ]. Peak #2 located 0.64 eV below the conduction band minimum corresponds to the Z 1/2 center which has been identified as carbon vacancies from annealing studies using DLTS and electron paramagnetic resonance (EPR) [ 16 , 25 , 45 , 46 ]. Peak #4 is located at 1.09 eV below the conduction band minimum and resembles the EH5 trap center.…”

“…Despite the promising aforementioned properties, a wide variety of microscopic and macroscopic crystal defects exist in the state-of-the-art 4H-SiC wafers which deteriorate the device performance [ 15 , 16 ]. In particular, micropipe defects in 4H-SiC single crystals, which are basically hollow-core threading screw dislocations, are the most potential crystal defects that deteriorate the device performance [ 17 , 18 ].…”

Improvement of β-SiC Synthesis Technology on Silicon Substrate

“…Through doping, the semiconductor properties of SiC can be tailored to yield both n-type and p-type materials [36,37]. These defects have been reported to impede the electrical and mechanical properties of the material, as corroborated by extensive studies [38,39]. Such defects are not just distinctive to silicon carbide but are a recurring theme across the broader category of semiconductors, each requiring its unique set of mitigative strategies.…”