Raman and reflection anisotropy spectroscopic studies of GaN and AlN growth on GaAs(100)

Initial nitridation of gallium arsenide to promote the nucleation and epita xy of gallium nitride (GaN) is prone to interface roughening and defect gen eration. This paper reports the deposition of gallium nitride (GaN) onto Ga As(100) substrates using two alternative approaches: either a low temperatu re aluminium nitride (AIN) buffer layer or a graded transition from gallium arsenide to gallium nitride growth. The interaction of nitrogen atoms with the GaAs(100) - c(4 x 4)As stabilized surface and the recrystallization of ALN buffer layers deposited at 400 degrees C were observed by reflection a nisotropy spectroscopy and dynamic optical reflectivity. Raman spectra of t he resulting films suggest the presence of mixed cubic and hexagonal GaN ph ases. (C) 1999 Elsevier Science S.A. All rights reserved.