R. Graupner et al., Study of interface reactions between Si and GaN at high temperatures usingscanning photoelectron microscopy and X-ray absorption spectroscopy, J CRYST GR, 217(1-2), 2000, pp. 55-64
Scanning photoelectron microscopy (SPEM) and X-ray absorption spectroscopy
have been used to study interface reactions between Si and GaN when GaN is
deposited on nitridated silicon substrates at high temperatures. The result
s show that the interface reactions between silicon and GaN are strongly de
pendent on the reaction temperature with the more severe reactions occurrin
g at higher temperatures. In addition to the observation of the direct reac
tion of nitrogen with the Si to form silicon nitride at the interface, the
chemical maps obtained with SPEM indicate that Si migrates to the top surfa
ce of the GaN layers. The migration of Si to the surface results in formati
on of SiNx on the top surface and in severe roughening of the GaN layers de
posited at 950 and 1010 degrees C, X-ray absorption data indicate that the
hexagonal structure forms at higher temperature while the cubic form of GaN
is the dominant structure at low temperature. The three-dimensional growth
of the hexagonal structure appears to be responsible for enhancement of th
e Si migration. (C) 2000 Published by Elsevier Science B.V.