CHANGES IN SURFACE-COMPOSITION OF GAN BY IMPURITY DOPING

Changes in the surface composition of GaN films by p- and n-type dopin g were studied using both Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). It was found that the surface compos ition of the GaN films was affected by impurity doping, i.e. the surfa ce of the p-type GaN film was enriched with gallium and that of the n- type GaN him with nitrogen, compared with that of the undoped GaN him. The surface composition of the GaN films by AES agrees with that by X PS after taking the contamination layer thickness into account. The ex perimental results thus obtained were discussed by taking account of t he formation energies of native defects in p- and n-type GaN.