On the First Demonstration and Analysis of the HTGB Induced Electrical Degradation of High Voltage SiC IGBT Devices

Silicon Carbide (SiC) possesses many superior electrical properties and is one of the most popular semi-conductor materials in the field of power electronics. SiC-based power devices feature high voltage withstand capability, low ON-resistance, and excellent thermal conductivity. Due to their bipolar conduction design, Insulated Gate Bipolar Transistors (IGBTs) achieve some of the highest power levels among discrete power devices. Therefore, SiC-based IGBT devices have significant research prospects and application potential. However, limited by the reliability of SiC devices, especially the gate oxide interface, there are currently no commercial SiC IGBT products available worldwide. In this study, the degradation of threshold voltage and conduction characteristics of 20 kV/15 A SiC IGBT devices under High Temperature Gate Bias (HTGB) stress is demonstrated and investigated for the first time. Furthermore, TCAD simulation is employed to establish the relationship between defect changes at the gate oxide interface and the degradation of threshold voltage (V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</inf>) and specific differential ON-resistance (R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">diff,sp</inf>) in SiC IGBT devices. The results indicate that the degradation of V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</inf> and R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">diff,sp</inf> is primarily affected by both gate voltage and temperature. The findings provide valuable insights for the design and application of SiC IGBT devices.