Group III-V semiconductor device and method for producing the same

[0072]FIGS. 1A to 1H are cross-sectional views of semiconductor structures for describing the steps of producing a light-emitting device through laser lift-off in Embodiment 1.

[0073]Firstly, a group III nitride semiconductor layer 11 is formed on a sapphire substrate 10 through epitaxial growth. A p-electrode 13 and a low-melting-point metal diffusion preventing layer 14 are formed on the semiconductor layer in the areas where light-emitting devices 12 are provided (FIG. 1A). The p-electrode may be formed from a metal having high optical reflectance and low contact resistance; for example, Ag, Rh, Pt, Ru, or an alloy containing such a metal as a primary component. Alternatively, the p-electrode may be made of, for example, Ni, an Ni alloy, or an Au alloy; or may be formed of a composite layer including a transparent electrode film (e.g., ITO film) and a highly reflective metal film. The low-melting-point metal diffusion preventing layer 14 is formed of, for example, a Ti / Ni-containi...

[0086]FIGS. 3A to 3G are cross-sectional views of semiconductor structures for describing the steps of producing a light-emitting device through laser lift-off in Embodiment 2.

[0087]Firstly, a group III nitride semiconductor layer 51 is formed on a sapphire substrate 50 through epitaxial growth. A p-electrode 53 and a low-melting-point metal diffusion preventing layer 54 are formed on the semiconductor layer in the areas where light-emitting devices 52 are provided (FIG. 3A). The p-electrode may be formed from a metal having high optical reflectance and low contact resistance; for example, Ag, Rh, Pt, Ru, or an alloy containing such a metal as a primary component. Alternatively, the p-electrode may be made of, for example, Ni, an Ni alloy, or an Au alloy; or may be formed of a composite layer including a transparent electrode film (e.g., ITO film) and a highly reflective metal film. The low-melting-point metal diffusion preventing layer 54 is formed of, for example, a Ti / Ni-containi...

[0096]As shown in FIG. 5, Embodiment 3 of the method of the invention is identical to Embodiment 2, except that the metal film 56 is also provided on the side surfaces of the light-emitting device 52 so as to cover the side-surface protective film 55. Since Al is a metal having high optical reflectance, light emission through a side surface of the light-emitting device 52 can be prevented by the metal film 56. Particularly when a side surface of the light-emitting device 52 is slanted, formation of the metal film 56 also on the slanted surface is preferred.

[0097]In Embodiments 2 and 3, a light-emitting device is produced. However, the present invention is not limited to the production of a light-emitting device, and encompasses any semiconductor devices which can be produced through the laser lift-off technique. Other than semiconductor devices produced from a group III nitride semiconductor, the invention is also applicable to semiconductor devices produced from a group III-V semic...