Patent ID: 7476909

Claim:
A light emitting device, comprising: a nitride semiconductor substrate and, on a first main surface of said nitride semiconductor substrate, an n-type nitride semiconductor layer, a p-type nitride semiconductor layer positioned further than said n-type nitride semiconductor layer viewed from said nitride semiconductor substrate, and a light generating layer positioned between said n-type nitride semiconductor layer and said p-type nitride semiconductor layer; wherein specific resistance of said nitride semiconductor substrate is at most 0.5 Ω·cm; the side of said p-type nitride semiconductor layer is mounted face-down and the light is emitted from a second main surface that is opposite to the first main surface of said nitride semiconductor substrate; a trench is formed in the second main surface of said nitride semiconductor substrate; said nitride semiconductor substrate is adapted to have n-type conductivity by oxygen doping, and an oxygen concentration in the range of 2E18/cm 3 to 2E19/cm 3 ; a two-dimensional shape of said nitride semiconductor substrate is a rectangle; a length of one side of the two-dimensional shape of said nitride semiconductor substrate is at least 1 mm and at most 4 mm; said trench has a V shaped cross section; a depth of said trench is at least 0.1 mm and at most 0.3 mm; a thickness of said nitride semiconductor substrate in the thickness direction where said trench is not formed is at least 0.2 mm and at most 0.4 mm; and n-electrodes are disposed only at four corners of the second main surface of the nitride semiconductor substrate.