US Patent 7294867 Semiconductor light generating device

The semiconductor light generating device comprises a light generating region 3, a first AlX1Ga1-X1N semiconductor (0≦X1≦1) layer 5 and a second AlX2Ga1-X2N semiconductor (0≦X2≦1) layer 7. In this semiconductor light generating device, the light generating region 3 is made of III-nitride semiconductor, and includes a InAlGaN semiconductor layer. The first AlX1Ga1-X1N semiconductor (0≦X1≦1) layer 5 is doped with a p-type dopant, such as magnesium, and is provided on the light generating region 3. The second AlX2Ga1-X2N semiconductor layer 7 has a p-type concentration smaller than the first AlX1Ga1-X1N semiconductor layer 5. The second AlX2Ga1-X2N semiconductor (0≦X2≦1) layer 7 is provided between the light generating region 3 and the first AlX1Ga1-X1N semiconductor layer 5.