III-nitride semiconductor light emitting device

1. A III-nitride compound semiconductor light emitting device including an active layer for generating light by recombination of an electron and a hole between an n-type nitride compound semiconductor layer and a p-type nitride compound semiconductor layer, the active layer being disposed over the n-type nitride compound semiconductor layer, comprising:

a masking film made of MgN and grown on the p-type nitride compound semiconductor layer; and

at least one nitride compound semiconductor layer grown after the growth of the masking film made of MgN.

2. The III-nitride compound semiconductor light emitting device of claim 1 ,

wherein the at least one nitride compound semiconductor layer comprises a first Al x In y Ga z N (x+y+z=1) layer.

3. The III-nitride compound semiconductor light emitting device of claim 2 ,

wherein the first Al x In y Ga z N (x+y+z=1) layer is composed of a plurality of islands.

4. The III-nitride compound semiconductor light emitting device of claim 1 ,

wherein the at least one nitride compound semiconductor layer comprises a first Al a In b Ga c N (a+b+c=1) layer and a second Al a In b Ga c N (a+b+c=1) layer, and the second Al a In b Ga c N (a+b+c=1) layer covers the whole surfaces of the masking film made of MgN and the first Al a In b Ga c N (a+b+c=1) layer.

5. The III-nitride compound semiconductor light emitting device of claim 4 ,

wherein the at least one nitride compound semiconductor layer further comprises a third Al e In f Ga g N (e+f+g=1) layer grown on the second Al a In b Ga c N (a+b+c=1) layer.

6. The III-nitride compound semiconductor light emitting device of claim 5 ,

wherein the second Al a In b Ga c N (a+b+c=1) layer is grown at a first temperature, the third Al e In f Ga g N (e+f+g=1) layer is grown at a second temperature, and the first temperature is lower than the second temperature.

7. The III-nitride compound semiconductor light emitting device of claim 1 ,

wherein the at least one nitride compound semiconductor layer comprises a first Al x In y Ga z N (x+y+z=1) layer, a second Al a In b Ga c N (a+b+c=1) layer and a third Al e In f Ga g N (e+f+g=1) layer, and the first Al x In y Ga z N (x+y+z=1) layer, the second Al a In b Ga c N (a+b+c=1) layer and the third Al e In f Ga g N (e+f+g=1) layer have p-type conductivity.

8. The III-nitride compound semiconductor light emitting device of claim 7 ,

wherein the at least one of the first Al x In y Ga z N (x+y+z=1) layer, the second Al a In b Ga c N (a+b+c=1) layer and the third Al e In f Ga g N (e+f+g=1) layer has a stack structure of a nitride compound semiconductor layer having p-type conductivity and a nitride compound semiconductor layer having n-type conductivity with thickness below 100 Å.

9. The III-nitride compound semiconductor light emitting device of claim 1 ,

wherein the at least one nitride compound semiconductor layer comprises an Al x In y Ga z N (x+y+z=1) layer composed of a plurality of islands and a supplementary Al e In f Ga g N (e+f+g=1) layer for covering the masking film made of MgN and the Al x In y Ga z N (x+y+z=1) layer composed of the plurality of islands.

10. The III-nitride compound semiconductor light emitting device of claim 9 ,

wherein the at least one nitride compound semiconductor layer further includes an Al a In b Ga c N (a+b+c=1) layer grown between the Al x In y Ga z N (x+y+z=1) layer composed of the plurality of islands and the supplementary Al e In f Ga g N (e+f+g=1) layer, at a lower temperature than the supplementary Al e In f Ga g N (e+f+g=1) layer.