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

Licheng Sun,Baoxing Duan,Yintang Yang

doi:10.1109/jeds.2021.3066811

Licheng Sun, Baoxing Duan + Show 1 more

Open Access

https://doi.org/10.1109/jeds.2021.3066811

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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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$20{\mu }\text{m}$ </tex-math></inline-formula> , which is 71.4% shorter than that of Conv. LIGBT of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$70{\mu }\text{m}$ </tex-math></inline-formula> . 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.

Highlights

In silicon-based power semiconductor devices, lateral insulated gate bipolar transistors (LIGBT) have become the core device of energy conversion and transmission in power electronic system after more than 20 years of development [1], [2], which is mainly used in high-voltage DC power supply, smart grid and rail transportation [3]
The proposed LIGBT makes full use of bulk Si substrate thickness to greatly improve breakdown voltage (BV), which achieves significantly improved trade-off performance between turnoff loss (Eoff ) and forward voltage drop (VF)
It can be clearly seen that the assisted depletion N-region (AD) structure formed in the AD LIGBT and PBAD LIGBT makes the depletion boundary of longitudinal space charge region expand greatly, and the equipotential lines distribution are more uniform, which realizes the full use of substrate thickness

Summary

Introduction

In silicon-based power semiconductor devices, lateral insulated gate bipolar transistors (LIGBT) have become the core device of energy conversion and transmission in power electronic system after more than 20 years of development [1], [2], which is mainly used in high-voltage DC power supply, smart grid and rail transportation [3]. Due to limitation of longitudinal electric field, conventional LIGBT with silicon-on-insulator (SOI) substrate is difficult to achieve very high breakdown voltage (BV) at the short drift length (LD) condition [4]. The proposed LIGBT makes full use of bulk Si substrate thickness to greatly improve BV, which achieves significantly improved trade-off performance between turnoff loss (Eoff ) and forward voltage drop (VF).

Results

Conclusion