| 摘要 |
PURPOSE:To enable the manufacture of a GND having a multilayer structure with the carrier concentration controlled at a time of crystal growth by a method wherein the cooling speed is controlled in the process of cooling a solution added with a dopant acting as an impurity for both polarities. CONSTITUTION:A mixture (raw material) of a fixed ratio of composition is uniformly dissolved. It is cooled to 905 deg.C at a cooling speed of 1 deg.C/min by the epitaxial growing method and then kept at this temperature for 5min. An N1 layer is formed in this process. Successively, a P1 layer is formed by cooling to 903 deg.C at a cooling speed of 0.05 deg.C/min. When the P1 layer is formed, a low carrier concentration layer is formed by cooling to 901 deg.C by the setting of the cooling speed at CR close to the region of inversion temperature. When this layer is formed, it is cooled to 891 deg.C and kept for 5min by an increase in the cooling speed to 2 deg.C/min. An N2 layer is formed in this process. Further, the cooling speed is set at 0.1 deg.C/min, and then a P2 layer is formed by cooling to 880 deg.C. Thereafter, the cooling speed is gradually increased with the decrease in the temperature inside a furnace, and a multilayer single crystal prepared after cooling inside the furnace is taken out. |
