Nitride semiconductor light emitting device and method for fabricating the same

1. A nitride semiconductor light emitting device comprising a nitride semiconductor multilayer film formed on a substrate,

wherein the nitride semiconductor multilayer film includes a light emitting layer and facets of a cavity, and is made of nitride semiconductor crystals;

a protective film made of aluminum nitride crystals is formed on at least one of the facets of the cavity; and

the protective film has a crystal plane whose crystal axes form an angle of 90 degrees with crystal axes of a crystal plane of the nitride semiconductor crystals constituting the facet of the cavity having the protective film formed thereon.

2. A nitride semiconductor light emitting device comprising a nitride semiconductor multilayer film formed on a substrate,

wherein the nitride semiconductor multilayer film includes a light emitting layer and facets of a cavity, and is made of nitride semiconductor crystals;

a protective film made of nitride crystals or oxynitride crystals is formed on at least one of the facets of the cavity;

a second protective film made of aluminum nitride crystals is formed on the protective film; and

the second protective film has a crystal plane whose crystal axes form an angle of 90 degrees with crystal axes of a crystal plane of the nitride semiconductor crystals constituting the facet of the cavity having the second protective film formed thereover.

3. The nitride semiconductor light emitting device of claim 2 , wherein the protective film is made of aluminum nitride crystals.

4. The nitride semiconductor light emitting device of claim 1 , wherein the protective film further has a crystal plane whose crystal axes are in parallel with the crystal axes of the crystal plane of the nitride semiconductor crystals constituting the facet of the cavity having the protective film formed thereon.

5. The nitride semiconductor light emitting device of claim 1 , wherein the amount of silicon at an interface between the protective film and the facet of the cavity having the protective film formed thereon is 1×10 20 atoms/cm 3 or less.

6. The nitride semiconductor light emitting device of claim 5 , wherein when the amount of silicon per unit area at the interface is calculated by secondary ion mass spectrometry, the amount of silicon at the interface is 2×10 14 atoms/cm 2 or less.

7. The nitride semiconductor light emitting device of claim 1 , wherein a protective film containing oxide or oxynitride is formed on the protective film.

8. The nitride semiconductor light emitting device of claim 2 , further comprising, on the second protective film, a protective film containing oxide or oxynitride.

9. The nitride semiconductor light emitting device of claim 7 , wherein the protective film containing oxide or oxynitride contains at least one element selected from the group consisting of Al, Si, Zr, Ti, Ta, Ga, Nb, and Hf.