S. Sonoda et al., Characterization of polarity of wurtzite GaN film grown by molecular beam epitaxy using NH3, JPN J A P 2, 39(3AB), 2000, pp. L202-L204
Effects of the initial nitridation of a sapphire(0001) substrate by NH3 on
the polarity of GaN{0001} film have been investigated by coaxial impact col
lision ion scattering spectroscopy. The polarity of ammonia-molecular beam
epitaxial (MBE) film grown on the substrate nitrided using NH3 is assigned
as (0001). The effect of the initial nitridation of the substrate by NH3 is
found to be contrary to that by nitrogen plasma, where the GaN film grown
on the nitrided substrate shows the polarity of.(000 (1) over bar). The pol
arity of GaN film grown by rf plasma-assisted MBE on the substrate which is
nitrided using NH3 is also (0001). These findings suggest the possibility
of polarity control of the grown GaN film by choosing the N source for init
ial nitridation of the substrate.