In a III group nitride compound semiconductor wherein light that has been
emitted in a light emitting portion formative layer is reflected by a
multilayered reflection layer that is provided between the light emitting
portion formative layer and sapphire substrate, it is desirable, for
increasing the reflection efficiency of the light that has been emitted
in the light emitting portion formative layer, that the multilayered
reflection layer be provided at a position that is as near to the light
emitting portion as possible. However, since the multilayered reflection
layer is high in resistance value and also high in power consumption,
locating the multilayered reflection layer near the light emitting
portion formative layer results in that the resistance value in the
vicinity of a relevant cathode electrode becomes increased. This raises
the problem that emission of light occurs only in part of the light
emitting portion formative layer. In the semiconductor light emitting
device of the present invention, a superlattice layer is provided between
the light emitting portion formative layer and the cathode electrode.