Plasma Etch Induced Surface Damage and Its Impacts on GaAs Schottky Diodes

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  • Author: Hong Shen, Peter Dai, and Ravi Ramanathan

Dry etch plays a very important role in fabrication of modern IIIV compound semiconductor devices. Compared to wet chemical etch, dry etch, which uses reactive gas plasma to remove substances chemically, has many advantages, such as better controllability, higher pattern reproducibility, and lower cost. Dry etch can induce surface damages that will affect physical and electrical properties of devices, due to high energy ion bombardments and the presence of reactive ion species [1-10]. These damages include surface roughness due to ion bombardment, surface contamination due to polymer deposition, and surface stoichiometry change due to preferential etching or layer intermixing. Highly damaged surfaces are least favored since the surfaces are not reproducible and cause high degree of non-uniformities in the electrical performances of the devices.