III–V nitride materials: an approach through amorphous GaAs 1 − xN x thin films

Abstract

We have studied the electrical properties and Raman scattering of nitrided amorphous GaAs thin films (a-GaAS 1 − x N x ) on Si substrates. Film deposition was carried out by RF sputtering of a GaAs target by adding a reactive gas (NH 3) to an Ar plasma. Raman spectroscopy showed that the incorporated N atoms take arsenic sites. For substitution ratios below a threshold value of 25–30%, the GaAs 1 − x N x thin films present a rather homogeneous phase, while beyond, a transition corresponding to an inhomogeneous and nanostructured material compound of amorphous GaN and GaAs has been observed. Current measurements ( J-V) on the a-GaAs 1 − x N x /c-Si heterostructures clearly show increasingly high resistivities (towards the insulating zone) with nitrogen incorporation. Furthermore, the C-V results obtained present MIS-like structure characteristics.