Atomic layer etching of InGaAs using sequential exposures of atomic hydrogen and oxygen gas

TL;DR

This paper presents an atomic layer etching process for InGaAs using sequential atomic hydrogen and oxygen exposures, achieving Angstrom-scale precision, low damage, and wafer-scale uniformity, which can improve III-V device fabrication.

Contribution

It introduces a novel ALE process for InGaAs with specific gas exposures, demonstrating high precision and smoothness for potential device applications.

Findings

Etch rate of 0.095 Å/cycle at 350°C

Sample remains atomically smooth after 200 cycles

Process suitable for gate recess etch in HEMT fabrication

Abstract

The high frequency performance and yield of III-V semiconductor devices such as InP HEMTs is negatively impacted by subsurface etch damage and non-uniform etch depth over the wafer. Atomic layer etching (ALE) has the potential to overcome this challenge because of its ability to etch with Angstrom-scale precision, low damage, and intrinsic wafer-scale uniformity. Here, we report an ALE process for InGaAs based on sequential atomic hydrogen and oxygen gas exposures. An etch rate of 0.095 \r{A}/cycle was observed at 350 {\deg}C using ex-situ spectroscopic ellipsometry. The sample remains atomically smooth after 200 cycles of ALE. This process could be employed as a gate recess etch step in InP HEMT fabrication to improve microwave performance and yield.