Development of Segmented 4H-SiC LGADs

TL;DR

This paper reports the first fabrication and initial testing of segmented 4H-SiC LGADs, demonstrating internal gain and effective segmentation for particle detection in harsh environments.

Contribution

It introduces the design, fabrication, and initial characterization of segmented 4H-SiC LGADs, a novel development in silicon carbide radiation detectors.

Findings

Demonstrated internal gain in segmented 4H-SiC LGADs.

Confirmed charge separation between adjacent strips.

Fabricated strip and pixel detectors with effective segmentation.

Abstract

The wide-bandgap semiconductor 4H-silicon carbide (4H-SiC) offers a compelling combination of radiation hardness, thermal stability, and high critical electric field for particle detection in harsh environments. To compensate for the comparatively low charge generation in SiC, the Low-Gain Avalanche Detector (LGAD) concept can be adopted to provide internal signal amplification. Building on three preceding generations of single-pad 4H-SiC LGAD prototypes fabricated by ion implantation, this work presents the design, fabrication, and initial characterization of segmented 4H-SiC LGAD devices -- the first fabricated and characterized devices reported. Strip detectors with 80~$\mu$m pitch and pixel arrays with 55 and 110~$\mu$m pitch were produced using multiple inter-channel isolation strategies, including geometric separation and oxide-filled trenches. Two-photon absorption transient current technique (TPA-TCT) measurements performed at ELI ERIC demonstrate clear charge separation between adjacent strips with internal gain, confirming functional segmentation.