Characterization of 4H-SiC Low Gain Avalanche Detectors (LGADs)

TL;DR

This paper reports on the fabrication and characterization of 4H-SiC LGADs, demonstrating high breakdown voltage, low leakage, and low-gain charge multiplication, with comparisons to PiN diodes and irradiation effects.

Contribution

It introduces the fabrication and detailed electrical characterization of 4H-SiC LGADs, highlighting their high breakdown voltage and charge multiplication capabilities.

Findings

High breakdown voltage confirmed by I-V and C-V measurements

Low leakage current observed in fabricated LGADs

Low-gain charge multiplication achieved after irradiation

Abstract

4H-SiC low gain avalanche detectors (LGADs) have been fabricated and characterized. The devices employ a circular mesa design with low-resistivity contacts and an SiO$_2$ passivation layer. The I-V and C-V characteristics of the 4H-SiC LGADs are compared with complementary 4H-SiC PiN diodes to confirm a high breakdown voltage and low leakage current. Both LGADs and PiN diodes were irradiated with $\alpha$ particles from a $^{210}_{84}\rm{Po}$ source. The charge collected by each device was compared, and it was observed that low-gain charge carrier multiplication is achieved in the 4H-SiC LGAD.