N2-H2 Remote Plasma Nitridation for GaAs passivation

A remote N2–H2 (a mixture of 97% N2–3% H2) rf plasma nitridation procedure has been developed to form a very thin (5Å) GaN layer successful in the electronic and chemical passivation of GaAs (100) surfaces. The interaction of the plasma with the GaAs surface has been controlled in situ and in real time by spectroscopic ellipsometry. By x-ray photoelectron spectroscopy, the composition of the passivating layer obtained by N2–H2 plasmas is found to be GaN. This makes the N2–H2 (a mixture of 97% N2–3% H2) nitridation completely different from the pure N2 nitridation which, in contrast, does not provide GaAs passivation, because the formation of GauN bonds accompanies with AsN and the segregation of elemental As at the GaN/GaAs interface. The stability of the chemical and electronic passivation is demonstrated by the nonoxidation and by the nondecaying behaviour of the photoluminescence efficiency of the GaAs passivated surface over months of air exposure. © 2002 American Institute of Physics. @DOI: 10.1063/1.1490414#