GaN ablation etching by simultaneous irradiation with F2 laser and KrF excimer laser

Abstract

GaN (0001)/c- Al 2 O 3 is etched by simultaneous irradiation with an F2 laser and a KrF excimer laser. The use of an F2 laser in addition to a KrF excimer laser reduces the roughness of the GaN surface compared with the case of KrF irradiation etching. An F2 laser, below the etching threshold, simultaneously irradiated with a KrF excimer laser, decreases the etching rate due to an increase in the absorption coefficient of the sample surface against the KrF excimer laser. A very sharp etching sidewall and flat surface are obtained when the etching depth reaches the Al2O3 substrate.