Implantation-free 2-step junction termination extension with 2-space modulated buffer trench regions for UHV 4H-SÍC GTO thyristors

A novel implantation-free 2-step junction termination extension (2S) with 2 space modulated buffer trench (2SMBT) zones is presented for ultrahigh voltage (>10kV) 4H-SiC gate turn off thyristor (GTO). The systematic studies on the optimization of the structure by Sentaurus TCAD tools were performed. The results show the 2SMBT structure introduced to the conventional 2S can effectively improve the BV by 19%, and the relative remaining dose window is significantly extended by a ratio of 742%, which means this structure can resist processing variations much more effectively.