Selective growth of (100)-, (110)-, and (111)-oriented MgO films on Si(100) by pulsed laser deposition

Abstract

Selective growth of singly oriented (110)-, (100)-, and (111)-MgO films on Si(100) substrates were obtained by pulsed laser deposition. The effects of deposition temperature, ambient oxygen pressure, and etching of the substrate on the structural properties of the films were studied. It is found that the crystalline orientations of the MgO films are determined at the initial deposition stage by the substrate temperature only. The ambient pressure during deposition and etching of the Si substrates only effect the crystalline quality. Both (110)- and (111)-oriented films show granular grain structures. The (100)-oriented films grown on etched Si substrates display similar granular structures. Those deposited on nonetched Si substrates, however, reveal distinctive columnar grains. The observed phenomena are discussed based on the theory of crystal growth. The mechanism of the orientation selection is attributed to the energy balance between the surface and the interface energies. The varied grain structures are explained by considering the mobility of adatoms in different situations.