Effects of ZnxMn1-xS buffer layer on nonpolar AlN growth on Si (100) substrate

Thin film growth of ZnxMn1-xS on a Si (100) substrate by sputtering was investigated for nonpolar AlN film growth on Si (100) substrate. The ZnxMn1-xS buffer layer reduces the large differences in thermal expansion coefficient and lattice constants between AlN and Si. Although the solubility of ZnS in MnS is less than 5% at 800 degrees C in bulk form, the insertion of a room-temperature MnS layer between ZnxMn1-xS and Si enabled (100)-oriented cubic-ZnxMn1-xS film growth even at x = 9.5%, which is a metastable phase and a phase separation region in bulk form. On the (100)-oriented cubic ZnxMn1-xS film, nonpolar AlN growth was achieved by sputtering. Furthermore, X-ray photoelectron spectroscopy measurements revealed that the ZnxMn1-xS film improved the stability of the AlN/ZnxMn1-xS interface. ZnxMn1-xS has the potential to enable nonpolar AlN growth on large-diameter Si (100) substrates.