Recent Progress in Selective Area Growth and Epitaxial Lateral Overgrowth of III-Nitrides: Effects of Reactor Pressure in MOVPE Growth

Abstract

Effects of reactor pressure on the epitaxial lateral overgrowth (ELO) via low pressure MOVPE have been studied in relation to the growth temperature. For the ELO GaN on SiO2 stripes along the 〈11-00〉 direction of the underlying GaN, by decreasing reactor pressures from 500 to 40 Torr or by increasing growth temperatures from 950 to 1050 °C, the (0001) surfaces become broad and the side walls are varied from inclined {112-2} surfaces to vertical {112-0} surfaces. For stripes along the 〈112-0〉 direction, the shapes of ELO GaN are independent of the reactor pressures and the growth temperatures. The mechanism of the morphological change is discussed based on the stability of the surface atoms. Typical ELO GaN layers with two-step growth are demonstrated and characterized in their crystalline properties.