Nanostructuring SiC by sequential plasma oxidation and reactive ion etching

TL;DR

This paper presents a novel nanostructuring process for silicon carbide (SiC) using sequential plasma oxidation and reactive ion etching, significantly reducing reflectance and enhancing UV detector performance.

Contribution

The study introduces a cyclical oxidation-etching process for SiC nanostructuring that achieves ultra-low reflectance and is compatible with device fabrication, improving UV detection capabilities.

Findings

Reflectance below 0.5% from 200 nm to 360 nm

Effective at incident angles up to 60 degrees

Consumes only about 1 micron of SiC

Abstract

Silicon carbide (SiC) is a highly promising material for the rapidly growing UV detection industry due to its visible-blindness, low dark current, and exceptional thermal and chemical stability. Despite these advantages, the performance of state-of-the-art SiC UV detectors remains limited due to high reflectance losses, even with the use of anti-reflection coatings. Here, we develop a reactive ion etching process for nanostructuring SiC to eliminate the reflectance losses. The process is based on consecutive oxidation and etching cycles. Consequently, a reflectance below 0.5% is achieved from deep UV (200 nm) to close to the SiC cut-off (~360 nm). The nanostructures are effective even at large incident angles as the reflectance remains practically unchanged up to 60 degrees. Furthermore, it is confirmed that the process consumes only ~1 um of SiC and is compatible with Al2O3 masking, thereby facilitating straightforward integration into device fabrication. The developed cyclical etching process could also prove useful for SiC etching in general.