Novel Low Loss LIGBT With Assisted Depletion N-Region and P-Buried Layer

Abstract

A novel low loss lateral insulated gate bipolar transistor (LIGBT) with high voltage level is designed and studied in this paper, and is proposed with assisted depletion N-region (AD) and P-buried layer (PB) in the bulk Si substrate, named PBAD LIGBT. The proposed PBAD LIGBT utilizes the idea of electric field modulation (EFM) to greatly improve the breakdown voltage, which optimizes the lateral and longitudinal electric field distribution by introduced high electric field peak. Therefore, compared with conventional (Conv.) LIGBT, the shortened drift length of proposed PBAD LIGBT is beneficial to improve the forward and switching characteristics at the same time, while maintaining the same breakdown characteristics. When the breakdown voltage reaches 360 V, according to the TCAD simulation results, the drift length of proposed PBAD LIGBT is $20{\mu }\text{m}$ , which is 71.4% shorter than that of Conv. LIGBT of $70{\mu }\text{m}$ . As a result of shortening drift length, the forward voltage drop and turn-off loss of proposed PBAD LIGBT are reduced by 51.4% and 68.5%, respectively. The simulated trade-off curves show that, proposed PBAD LIGBT achieves significantly improved trade-off performance between turn-off loss and forward voltage drop than that of Conv. LIGBT, including PB LIGBT and AD LIGBT.

Keywords

• LIGBT
• breakdown voltage
• electric field modulation (EFM)
• turn-off loss
• forward voltage drop