50 mm diameter Sn-doped (0 0 1) β-Ga2O3 crystal growth using the vertical Bridgeman technique in ambient air

Abstract

50 mm-diameter Sn-doped β-Ga2O3 crystals with growth orientation perpendicular to (001) plane were grown with the newly-developed resistance heating vertical Bridgeman furnace using platinum–rhodium alloy crucibles in ambient air. Weak low angle grain boundaries and several small grains were detected on the both-side mirror-polished 50 mm-diameter (001) wafer, using high resolution refraction x-ray topography. However, no imperfections were observed over the whole wafer area when using crossed polarizer analysis. Measured values of both the full width at half maximum and the dislocation densities were widely distributed in the wafer, ranging from 10 to 50 arcsec and 100 to 2000 /cm2 respectively with no distinctive correlations among them. The Sn-doped crystals with concentrations ranging from 5 × 1017 to 5 × 1018 atom/cm3 could be grown by Sn-doping in a range from 0.05 to 0.1 mol%, and (001) oriented, 50 mm-diameter n-type oxide semiconductor wafers with a carrier density of 3.6 × 1018 /cm3, a mobility of 60 cm2/Vsec and a resistivity of 0.03 Ω-cm, were obtained from a 0.1 mol% Sn-doped crystal.