| 摘要 |
In a separation layer removing process alpha , temperature in a reaction chamber (heat treatment temperature Tx) is raised to about 1000 DEG C and a separation layer A is evaporated through thermal decomposition, to thereby separate about 10 mu m in thickness of protection layer B from a base substrate side (a sapphire substrate 101 comprising a buffer layer 102). Because decomposition temperature of the separation layer A is higher than growth temperature of the protection layer B (about 650 DEG C) and lower than growth temperature of the semiconductor crystal C (about 1000 DEG C), the separation layer A vanishes (evaporates) by thermal decomposition, which generates this separation process. Accordingly, a semiconductor crystal having a cross sectional structure shown in FIG. 2B is obtained. By employing the protection layer B which is independent from the base substrate side as another crystal growth substrate, dislocations and cracks may not be generated by stress owing to difference of lattice constants or difference of thermal expansion coefficients, and a semiconductor crystal layer C (GaN single crystal) of high quality can be obtained. <IMAGE> |
