A single layer hydrogen silsesquioxane (HSQ) based lift-off process for germanium and platinum

TL;DR

This paper introduces a novel single-layer hydrogen silsesquioxane (HSQ) lift-off process for patterning germanium and platinum at the nanoscale, utilizing HF etching and ultrasonic agitation to improve quality.

Contribution

It is the first to investigate HSQ as a negative tone resist for lift-off, demonstrating its effectiveness for nanometer-scale patterning of germanium and platinum.

Findings

Successful lift-off of germanium and platinum using HSQ

HF concentration affects HSQ removal efficiency

Ultrasonic agitation reduces flake formation

Abstract

Primarily used as etch mask, single layer hydrogen silsesquioxane has never been investigated for lift-off technique. In this article, we propose a new technique where a single layer of hydrogen silsesquioxane, a negative tone electron beam resist, is used to make lift-off of germanium and platinum. Removal of exposed hydrogen silsesquioxane is tested for various concentrations of hydrofluoric acid. Ultrasonic agitation is also used to reduce the formation of flakes due to accumulation of matter (evaporated metal in our case) along the sidewalls of the lift-off narrow slots. Results demonstrate potential in applying the hydrogen silsesquioxane as a negative tone lift-off resist to pattern nanometer scale features into germanium and platinum layers.