Optical and electrical characterization of n-GaAs surfaces passivated by N2-H2 plasma

The passivation of GaAs (100) surface has been performed by using remote N-2-H-2 (3% in H-2) RF plasma nitridation. The samples, consisting of n-doped GaAs wafers, show photoluminescence enhancement when the nitridation time and exposure to the plasma are in a narrow temporal window, so that a very thin (about 10 Angstrom) GaN layer is deposited on the GaAs surface. Pure N-2 nitridation does not provide an efficient passivation, because it results in GaN layers with As and AsNx segregation at the GaN/GaAs interface. Increase of Au-GaAs Schottky barrier with the insertion of GaN interlayer and improvement of current-voltage characteristic have been observed. (C) 2002 Elsevier Science B.V. All rights reserved.