X-ray photoelectron spectroscopic investigation of the GaAs nitridation mechanism with an ECR plasma source

The mechanism of arsenic replacement by nitrogen to produce beta-GaN in GaA s(001) samples exposed to the flux of an electron cyclotron resonance (ECR) plasma source is discussed on the basis of core level photoemission and ph otodiffraction data collected in situ. An amorphisation step is clearly evi denced which could favour nitrogen incorporation but should be kept at a mi nimum in order to maintain a cubic crystallographic template to stabilize-t he Ga-N bonds into epitaxial beta-GaN.