| abstract |
There is disclosed a semiconductor device formed on a sapphire substrate, for example, a blue LED of a double-hetero structure having a laminated structure which comprises a first cladding layer made of a first conductivity type gallium nitride based semiconductor, an active layer made of a gallium nitride based semiconductor into which impurity is not doped intentionally, and a second cladding layer made of a second conductivity type gallium nitride based semiconductor which being opposite to the first conductivity type on a sapphire substrate. A surface of the sapphire substrate is polished to have optical transmissivity of more than 60%. |