Growth of completely (110)- and (111)-oriented MgO films on H-terminated (100) silicon substrate by pulsed laser deposition

Thin films of MgO have been grown on H-terminated Si (100) substrates by pulsed laser deposition. The completely (110)-oriented films were obtained at ambient pressure of 10−3 Pa and at various substrate temperatures from 400 to 750°C. If the ambient pressure is higher, the prepared MgO films are (111)-oriented. The (110)-oriented films have a larger lattice constant along the [110] direction comparing to that of the bulk MgO; while the lattice constant of the (111)-oriented films along the [111] direction is almost the same as that of the bulk MgO. Atomic force microscopy measurements showed the surface of deposited films is smooth with roughness less than 30 nm. These results are explained by taking into account of the interactions between MgO species and substrate surface.