III–V nitride materials: an approach through amorphous GaAs1 − xNx thin films

We have studied the electrical properties and Raman scattering of nitrided amorphous GaAs thin films (a-GaAS1 − xNx) on Si substrates. Film deposition was carried out by RF sputtering of a GaAs target by adding a reactive gas (NH3) 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 GaAs1 − xNx 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-GaAs1 −xNx/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.