Cleaning of AlN and GaN surfaces

Successful ex situ and in situ cleaning procedures for AlN and GaN surfaces have been investigated and achieved. Exposure to HF and HCl solutions prod uced the lowest coverages of oxygen on AlN and GaN surfaces, respectively. However, significant amounts of residual F and Cl were detected. These halo gens tie up dangling bonds at the nitride surfaces hindering reoxidation. T he desorption of F required temperatures >850 degrees C. Remote H plasma ex posure was effective for removing halogens and hydrocarbons from the surfac es of both nitrides at 450 degrees C, but was not efficient for oxide remov al. Annealing GaN in NH3 at 700-800 degrees C produced atomically clean as well as stoichiometric GaN surfaces. (C) 1998 American Institute of Physics . [S0021-8979(98)02821-7].