Advances in Atomic Layer Etch for Quantum and more

Abstracts

Introduction to the webinar and overview of Atomic Layer Etch
Dr Russ Renzas, Oxford Instruments Plasma Technology

Atomic Layer Etch (ALE) offers three advantages as compared to standard ICP RIE: precise etch rates, surface smoothening, and reduced damage. We will introduce both types of ALE – anisotropic and isotropic – and discuss key use cases.

Bias-pulsed Atomic Layer Etch of SiC
Julian Michaels, University of Illinois

Atomic Layer Etching (ALE) is a cyclical etch that removes single atomic layers at a time. ALE methods exist for many semiconductors and is inimitable in precision etching; however, ALE is slow relative to other etching methods because reagent gases are purged between each cycle. This talk presents a novel approach to ALE for 4H-SiC that pulses only the plasma DC bias. This bias-pulsed ALE is approximately ten times faster than conventional ALE because gases are not purged. Atomic force microscopy scans show that this process can substantially smooth the etched surface.

Isotropic plasma-thermal atomic layer etching of aluminum nitride for quantum photonics applications
Prof. Austin Minnich, Professor, California Institute of Technology (Caltech)

Aluminum nitride is a material of significant interest for quantum photonic integrated circuits owing to its simultaneous second and third-order optical nonlinearities. However, surface roughness induced light scattering originating from nano fabrication imperfections is a major limitation on various figures of merit. In this talk, I will describe an isotropic atomic layer etching (ALE) process we have developed which enables the etching and smoothing of AlN film surfaces with Angstrom precision. The process is based on the fluorination of AlN using an SF6 plasma, followed by a ligand-exchange reaction with trimethylaluminum to yield etching. A maximum etch rate of 1.9 A/cycle was observed at 300 C along with a 35% decrease in surface roughness after 50 cycles. The process has potential to advance the application of AlN for quantum photonics.