The misfit dislocation density in an interface (27b) is greater than the misfit dislocation density in an interface (27a).

The III-nitride material regions) advantageously have a low dislocation density and, in particular, a low screw dislocation density.

The p-type cladding layer (309) has portion of high dislocation density and portion of low dislocation density.

The dislocation density of the light emitting layer is partly low.

To lower the dislocation density the mask method is used.

The membrane layer provides a dislocation density of no more 106 disclocations/cm2.

The dislocation density of the second region (17b) is smaller than that of the substrate (13).

The dislocation density is the accumulation of stress/imperfections in the metal crystal lattice of the metal.

The dislocation density of the third region (17c) is smaller than that of the first region (17a).

The first monocrystalline substrate (11) has a lower dislocation density than that of the support (30).

Provided is a semiconductor element having a buffer layer that reduces dislocation density.

The dislocation density of the GaN self-supporting substrate (2) is 1x108cm-2 or less.

The dislocation density (D) of the second AlY1InY2Ga1-Y1-Y2N layer (15) is 1 x 108cm-2.

Whereby, it is possible to obtain a high-quality semiconductor crystal free from cracks and low in dislocation density.

As a reslt, the upper layer above the spaces (13a), (13b) turns crystalline with a low dislocation density.