High resolution reactive ion etching of GaN and etch-induced effects

We have developed a process using electron beam lithography and reactive io n etching for the high resolution pattern transfer of GaN. 150 nm dots have been fabricated in GaN successfully. Photoluminescence, scanning electron microscopy, and x-ray photoelectron spectroscopy have been employed to comp are the damage inflicted on the GaN surfaces after SF6 and Ar plasma exposu res. Near-band-edge luminescence analysis indicates the existence of a high er concentration of donors on the top 100 nm of the GaN surface after Ar as supposed to SF6 plasma exposure. An order of magnitude decrease in the rat io of the yellow to the band-edge luminescence intensity is found in the sa mples subjected to lower ion energies. Formation of pits is observed on the substrate surfaces after plasma treatment. Nitrogen deficient surfaces lim ited to the top few monolayers, as well as defect propagation down to 100 n m, exist in our plasma exposed GaN samples. (C) 1999 American Vacuum Societ y. [S0734-211X(99)10006-4].