Purification of β-Ga2O3 crystals by the zone refining method

The reduction of Si concentration in β-Ga2O3 crystals by the zone refining method was investigated. By the chemical analysis of a quenched β-Ga2O3 crystal coexisting with its melt at high temperature, the segregation coefficient for Si was estimated to be 0.54, revealing that Si as impurity is excluded from the solid to the liquid phases of β-Ga2O3 and zone refining is effective for purification. By repeating the zone refining process three times, the Si concentration showed a tendency to decrease gradually, as a numerical calculation simulates, and reached a level of ∼1017 cm−3.