[7a-A402-1~10] 8.4 Plasma etching

[7a-A402-10] Chemically chlorine radical-etch of GaN at elevated temperatures

〇Kenji Ishikawa¹, Zecheng Liu¹, Masato Imamura¹, Takayoshi Tsutsumi¹, Hiroki Kondo¹, Osamu Oda¹, Makoto Sekine¹, Masaru Hori¹ (1.Nagoya University)

Keywords:Plasma etching, Galium nitrides, Plasma-induced damages

Surface chemical reactions on the GaN surface with Cl radicals are thermally enhanced in the high-temperature Cl₂ plasma etching of GaN, resulting in the formation of etch pits and thereby roughened the surface. Simultaneous irradiation of ultraviolet (UV) photons in Cl₂ plasma emissions with wavelengths of 258 and 306 nm reduces the surface chemical reactions because of the photodissociation of both Ga and N chlorides, which leads to a suppression of the increase of surface roughness. As compared with Si-related materials, we point out that photon-induced reactions should be taken into account during the plasma processing of wide-bandgap semiconductors.