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

The passivation of GaAs (1 0 0)surface has been performed by using remote N2 –H2 (3%in H2 )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 (A)GaN layer is deposited on the GaAs surface.Pure N2 nitridation does not provide an ef .cient passivation,because it results in GaN layers with As and AsN x 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. r 2002 Elsevier Science B.V.All rights reserved. PACS: 73.20;73.30;78.55 Keywords: GaAs;Photoluminescence;Nitridation;Schottky barrier