Promise and Challenges of High-Voltage SiC Bipolar Power Devices

Tsunenobu Kimoto,Jun Suda,Kyosuke Yamada,Hiroki Niwa

doi:10.3390/en9110908

Tsunenobu Kimoto, Jun Suda + Show 2 more

Open Access

https://doi.org/10.3390/en9110908

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Journal: Energies	Publication Date: Nov 3, 2016
Citations: 66	License type: CC BY 4.0

Affiliation: Kyoto University

Abstract

Although various silicon carbide (SiC) power devices with very high blocking voltages over 10 kV have been demonstrated, basic issues associated with the device operation are still not well understood. In this paper, the promise and limitations of high-voltage SiC bipolar devices are presented, taking account of the injection-level dependence of carrier lifetimes. It is shown that the major limitation of SiC bipolar devices originates from band-to-band recombination, which becomes significant at a high-injection level. A trial of unipolar/bipolar hybrid operation to reduce power loss is introduced, and an 11 kV SiC hybrid (merged pin-Schottky) diodes is experimentally demonstrated. The fabricated diodes with an epitaxial anode exhibit much better forward characteristics than diodes with an implanted anode. The temperature dependence of forward characteristics is discussed.

Highlights

Silicon carbide (SiC) has received increasing attention as a wide bandgap semiconductor well suited for high-voltage power devices
The forward characteristics were simulated by changing the carrier lifetime in a wide range
The ambipolar diffusion constant (Da ) and ambipolar μs diffusion length (La ) of excess 10 carriers are given by the following equations: μs μs τSRH D

Summary

Introduction

Silicon carbide (SiC) has received increasing attention as a wide bandgap semiconductor well suited for high-voltage power devices. SiC (4H polytype) unipolar devices such as metal-oxide-semiconductor field effect transistors (MOSFETs) and Schottky barrier diodes (SBDs) with blocking voltages of 600–1700 V have been commercialized, demonstrating substantial reduction of power loss in various power conversion systems. SiC power MOSFETs have currently been developed [6,7,8], and 15 kV SiC MOSFETs have been demonstrated [8]. These very high-voltage SiC MOSFETs can be fabricated with process technology similar to that used for 1 kV-class SiC MOSFETs, though some modifications are required in the cell design and termination structure. The specific on-resistance (Ron ) of power MOSFETs significantly increases with increasing the blocking voltage (V B ), following the relationship of

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Results

Discussion

Conclusion