Development of InSb dry etch for mid-IR applications

Article history: Received 20 October 2015 Received in revised form 18 December 2015 Accepted 21 December 2015 Available online 22 December 2015 We present a new chlorine-free dry etching process which was used to successfully etch indium antimonide grown on gallium arsenide substrates while keeping the substrate temperature below 150 °C. By use of a reflowed photoresist mask a sidewall with 60 degree positive slope was achieved, whereas a nearly vertical one was obtained when hard masks were used. Long etch tests demonstrated the non-selectivity of the process by etching through the entire multi-layer epitaxial structure. Electrical and optical measurements on devices fabricated both by wet and dry etch techniques provided similar results, proving that the dry etch process does not cause damage to the material. This technique has a great potential to replace the standard wet etching techniques used for fabrication of indium antimonide devices with a non-damaging low temperature plasma process. © 2016 Elsevier B.V. All rights reserved.