Crystallographic Wet Chemical Etching of p-Type GaN

Abstract

We demonstrate crystallographic wet chemical etching of p‐type GaN with etch rates as high as 1.2 μm/min. Etchants used include molten KOH, KOH dissolved in ethylene glycol, aqueous tetraethylammonium hydroxide, and phosphoric acid at temperatures ranging from 90 to 260°C. The observed crystallographic p‐GaN etch planes are (0001), , and The etch rates follow an Arrhenius characteristic with activation energies varying from 21 kcal/mol for KOH‐based solutions to 33 kcal/mol for The etch rate and crystallographic nature for the various etching solutions are independent of conductivity, as shown by seamless etching of a p‐GaN/undoped, high‐resistivity GaN homojunction and by comparison of the etch rates of p‐GaN with n‐GaN. © 2000 The Electrochemical Society. All rights reserved.