Room-temperature photoenhanced wet etching of GaN

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 Angstrom/min (HCl) and up to a few thousand Angstrom/min (KOH) have been measured for: unintentionally doped n-type films of thickness (1-2 mu m) 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. (C) 1996 American Institute of Physics.