Theoretical and Experimental Study of 13.4 kV/55 A SiC PiN Diodes with an Improved Trade-Off between Blocking Voltage and Differential On-Resistance.

Yuewei Liu,Zhiguo Zhang,Ruixia Yang,Yongwei Wang,Xiaochuan Deng

doi:10.3390/ma12244186

Abstract

In this paper, a 13.4 kV/55 A 4H-silicon carbide (SiC) PiN diode with a better trade-off between blocking voltage, differential on-resistance, and technological process complexity has been successfully developed. A multiple zone gradient modulation field limiting ring (MGM-FLR) for extremely high-power handling applications was applied and investigated. The reverse blocking voltage of 13.4 kV, close to 95% of the theoretical value of parallel plane breakdown voltage, was obtained at a leakage current of 10 μA for a 100 μm thick, lightly doped, 5 × 1014 cm−3 n-type SiC epitaxial layer. Meanwhile, a fairly low differential on-resistance of 2.5 mΩ·cm2 at 55 A forward current (4.1 mΩ·cm2 at a current density of 100 A/cm2) was calculated for the fabricated SiC PiN with 0.1 cm2 active area. The highest Baliga’s figure-of-merit (BFOM) of 72 GW/cm2 was obtained for the fabricated SiC PiN diode. Additionally, the dependence of the breakdown voltage on transition region width, number of rings in each zone, as well as the junction-to-ring spacing of SiC PiN diodes is also discussed. Our findings indicate that this proposed device structure is one potential candidate for an ultra-high voltage power system, and it represents an option to maximize power density and reduce system complexity.

Highlights

There is no doubt that 4H-silicon carbide (SiC) material will play an increasingly important role in ultra-high voltage supply system or low-power loss industrial applications, given its excellent intrinsic structure and physical properties, especially in the future smart grids which contain high voltage DC power distribution and flexible AC transmission [1,2,3]
Fabrication benefits could lead to the field limiting ring becoming one of the most popular and most commonly used terminal structures, compared to the junction termination extension (JTE) edge terminal that requires multiple injections
We proposed and demonstrated a large area SiC PiN diode rated at 10 kV using a novel multi-zone gradient modulation field limiting ring (MGM-FLR) structure without increasing the complexity of the technological process or the cost of the processing steps

Summary

Introduction

There is no doubt that 4H-silicon carbide (SiC) material will play an increasingly important role in ultra-high voltage supply system or low-power loss industrial applications, given its excellent intrinsic structure and physical properties, especially in the future smart grids which contain high voltage DC power distribution and flexible AC transmission [1,2,3]. Fabrication benefits could lead to the field limiting ring becoming one of the most popular and most commonly used terminal structures, compared to the JTE edge terminal that requires multiple injections. Field limiting rings are often difficult to optimize and fabricate for ultra-high voltage SiC devices, because of their simple structure. Reports on SiC PiN diodes with extremely high-power capabilities (both ultra-high voltage and high forward current) are still limited [16,17]. We proposed and demonstrated a large area SiC PiN diode rated at 10 kV using a novel multi-zone gradient modulation field limiting ring (MGM-FLR) structure without increasing the complexity of the technological process or the cost of the processing steps. The highest Baliga’s figure-of-merit (BFOM) is achieved as high as 72 GW/cm for the fabricated SiC PiN diode

Device Structure and Fabrication

Experimental Results and Discussion

Conclusions