THE EVOLUTION OF A-GAAS1-XNX C-GAAS INTERFACE STATES AS A FUNCTION OFAR-NH3 PLASMA/

This work concerns investigations on electrical properties of amorphou s GaAs1-xNx thin films grown on GaAs substrates. Film deposition was c arried out by RF sputtering of a GaAs target by adding a nitrogen carr ier gas (NH3) to an Ar plasma. Chemical etching of substrates followed by different plasma treatments (like reverse bias and/or NH3 glow dis charge) prior to film deposition have been studied. The effects of sub strate and growth temperature and of total pressure in the reactor hav e been analysed. Electrical characteristics (C-V and C-V(T)) have enab led us to put in evidence the evolution of interface states of the a-G aAs1-xNx/c-GaAs junctions. The amorphous GaAs1-xNx thin films are pote ntially interesting to be considered for GaAs-based MIS structures, du e to their relatively high resistivity values, or as passivating layer s on GaAs devices. (C) 1997 Elsevier Science S.A.