Laser ablation of via holes in GaN and AlGaN∕GaN high electron mobility transistor structures

Abstract

Laser drilling for through-via holes was performed with a Nd:YVO4 laser for an AlGaN∕GaN high electron mobility transistor (HEMT) structure on a SiC substrate. Current-voltage (I-V) characteristics, transconductance, and small signal characteristics before and after laser drilling were compared to examine the effect of laser drilling on device performance. The electrical characteristics of the HEMTs did not show significant change after laser drilling, even when performed in close proximity to the device. Laser drilling was found to be a fast and safe technique to drill via hole in AlGaN∕GaN HEMT structure and provides an alternative to dry etching for creation of these vias.