Bias-pulsed atomic layer etching of 4H-silicon carbide producing subangstrom surface roughness

A new approach to atomic layer etching (ALE) has been demonstrated, and its application to 4H-SiC is reported here. By pulsing only the DC bias for an Ar/Cl-2 inductively coupled plasma-reactive ion etching system, the etch cycle duration is reduced by more than an order of magnitude relative to conventional ALE processes. Gas flows are not changed throughout the ALE process. With this process protocol, we achieved an etch rate of 2.48 +/- 0.09 angstrom/cycle with 6 s cycles, an RMS surface roughness (R-q) of 0.83 +/- 0.08 angstrom, and an ALE synergy value of S = 99%. The parameters explored within this ALE process demonstrate effective subangstrom smoothening of 4H-SiC surfaces and is well-suited for a variety of classical and quantum device nanofabrication. (c) 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http.//creativecommons.org/licenses/by/4.0/).

Automated summary

A new approach to atomic layer etching (ALE) for 4H-SiC is demonstrated, with a significantly reduced etch cycle duration compared to conventional ALE processes. The etch rate achieved is 2.48 +/- 0.09 angstrom/cycle with 6 s cycles, accompanied by a low surface roughness and high ALE synergy value. This ALE process shows potential for precise nanofabrication in classical and quantum device applications.