Growth of MgO on Si(100) and GaAs(100) by laser ablation

Abstract

Thin films of MgO have been grown on Si(100) and GaAs(100) by ablation of a Mg target in an oxygen atmosphere using the fundamental frequency of a Nd:YAG laser. An ambient oxygen pressure of 5×10 −5 Torr was found to be optimal for growth on both substrates; however, different substrate temperatures were required: 500°C for growth on Si; 350°C for growth on GaAs. This low growth temperature ensures minimal arsenic desorption from the GaAs substrate. The MgO films on both substrates are (100) oriented, as shown by X-ray θ–2 θ scans. The epitaxy of these crystals is confirmed by pole figure measurements of off-axis MgO reflections, which also indicate that the MgO lattices are oriented cube on cube with the substrate lattice, i.e. MgO 〈100〉 ‖Si 〈100〉 and MgO 〈100〉 ‖GaAs 〈100〉.