III-V NITRIDE MATERIALS - AN APPROACH THROUGH AMORPHOUS GAAS1-XNX THIN-FILMS

We have studied the electrical properties and Raman scattering of nitr ided amorphous GaAs thin films (a-GaAs1-xNx) on Si substrates. Film de position was carried out by RF sputtering of a GaAs target by adding a reactive gas (NH3) to an Ar plasma. Raman spectroscopy showed that th e incorporated N atoms take arsenic sites. For substitution ratios bel ow a threshold value of 25-30%, the GaAs1-xNx thin films present a rat her homogeneous phase, while beyond, a transition corresponding to an inhomogeneous and nanostructured material compound of amorphous GaN an GaAs has been observed. Current measurements (J-V) on the a-GaAs1-xNx /c-Si heterostructures clearly show increasingly high resistivities (t owards the insulating zone) with nitrogen incorporation. Furthermore, the C-V results obtained present MIS-like structure characteristics. ( C) 1997 Elsevier Science S.A.