Amorphous GaAs1-xNx thin films on crystalline Si substrates: growth and characterizations

This work deals with the growth and study of a new nitride in thin films: GaAs1-xNx. The material is deposited in its amorphous form on crystalline Si substrates by means of RF sputtering of a GaAs target in an atmosphere of argon and ammonia. Raman spectroscopy used to study the physicochemical properties of the film structure pointed out that GaAs1-xNx is a wide gap material which is formed by the substitution of arsenic by nitrogen in the GaAs network (J. Bandet, K. Aguir, D. Lollman, A. Fennouh, H. Carchano, Jpn. J. Appl. Phys., 36 (1997) 11. In order to investigate the electrical properties of GaAs1-xNx in view of potential applications in optoelectronic systems, J-V and C-V characteristics have been performed. J-V results show that the heterostructures exhibit a drastic increase in resistivity with nitrogen incorporation. The conduction passes from a diode-type one for x=0 to an approximately symmetrical one with nitridation, i.e, for x>0. The films present convenient high resistivity values for insulating character consideration. Furthermore, C-V results obtained present a manifest MIS-like behaviour with however the existence of a flat-band voltage (V-FB). (C) 1997 Elsevier Science S.A.