Method for fabricating a HEMT device in an atomic layer etching reactor and use of the method in fabrication of a gallium-nitride-based HEMT

Abstract

The present invention relates to a method for fabricating a high electron mobility transistor device in an atomic layer etching reactor. The method comprises: providing a wafer comprising a selectively masked gallium nitride layer; and subjecting the selectively masked gallium nitride layer for an etching process comprising alternating surface modification and removal steps. The surface modification steps are performed under reactive gas flow. The removal steps are performed using a low-energy particle beam primarily comprised of noble gas species. A plasma is maintained continuously throughout the etching process. The surface modification and removal steps are repeated or merged to achieve a cyclic or quasi-continuous atomic-layer etching process transitioning to a continuous dry etch mode in which reactive gases and plasma are continuously supplied while maintaining self-limiting surface kinetics once steady-state self-limiting conditions are reached.

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