Room-temperature photoenhanced wet etching of GaN

Abstract

Laser-enhanced, room-temperature wet etching of GaN using either dilute HCl:H2O (1:10) or 45% KOH:H2O(1:3) is reported. Etch rates of a few hundred Å/min (HCl) and up to a few thousand Å/min (KOH) have been measured for unintentionally doped n-type films of thickness (1–2 μm) grown by MOCVD on a sapphire substrate. The etching is thought to take place photoelectrochemically with holes and electrons generated by incident illumination from 4.5 mW of HeCd laser power enhancing the oxidation and reduction reactions in an electrochemical cell.