THE GROWTH OF SINGLE CRYSTALLINE GAN ON A SI SUBSTRATE USING ALN AS AN INTERMEDIATE LAYER

MOVPE growth of GaN films on Si(111) substrates has been studied. A thin single crystal of AlN is found to be an effective intermediate layer for the growth of single crystalline GaN films with flat surfaces. Reflection high-energy electron diffraction (RHEED) pattern observation and X-ray diffraction measurements revealed that crystalline quality was much improved by using the AlN intermediate layer. Photoluminescence (PL) measurements at room temperature (RT) showed that the optical properties were also improved. X-ray diffraction studies and PL measurements at 4.2 K showed that the GaN films were deformed under a tensile stress due to the difference in the thermal expansion coefficient between GaN and Si.