| 摘要 |
PURPOSE: To protect a clad layer against cracking by specifying the thickness of the clad layer for emission layer composed of a group III nitride semiconduc tor having three layer structure where an active layer is sandwiched by clad layers. CONSTITUTION: Al0.1 Ga0.9 N is deposited by 4μm on high carrier concentration n<+> layer 3 of various heights and the cracking conditions are observed. No crack is observed in the Al0.1 Ga0.9 N deposited on the layer 3 of 5μm thick. Consequently, the thickness of high carrier concentration n<+> layer 3 is set in the range of 2-5μm. Thickness of the clad layer 4, 61 is preferably set in the range of 0.5-1μm thus obtaining a low balance device excellent in crack prevention performance and conductivity of n<+> layer. More preferably, the compositional ratio of Al is set at 0.1 or less for the clad layer in order to eliminate cracking. Consequently, cracking can be prevented when the thickness of clad layer is set in the range of 0.5-2μm. |
