Patent ID: 7271422

Claim:
A semiconductor optical device comprising: a first conductive type semiconductor region including a first semiconductor portion and a second semiconductor portion, the first and second semiconductor portions being made of nitride mixed semiconductor crystal, the first semiconductor portion having a first region and a second region, the first and second regions being arranged along a predetermined plane, the second semiconductor portion being provided on the first region of the first semiconductor portion, the second semiconductor portion having a side; a second conductive type semiconductor region made of nitride mixed semiconductor crystal, the second conductive type semiconductor region including a first region and a second region, the first region being different from the second region, the second region of the first conductive type semiconductor region and the second region of the second conductive type semiconductor region constituting a pn junction, the sides of the second semiconductor portion and the second region of the second conductive type semiconductor region constituting a pn junction; and an active layer made of nitride mixed semiconductor crystal, the active layer being provided between the second semiconductor portions of the first conductive type semiconductor region and the first region of the second conductive type semiconductor region, a bandgap energy of the first conductive type semiconductor region being greater than that of the active layer, a bandgap energy of the second conductive type semiconductor region being greater than that of the active layer.