Method for producing a semiconductor device
The present invention provides a method for producing a semiconductor device exhibiting the improved emission efficiency by reducing a strain between a p-contact layer and a transparent electrode. A transparent electrode made of IZO (Zinc-doped Indium Oxide) was formed on a p-type contact layer by vapor deposition or sputtering. Subsequently, a p-type cladding layer and a p-type contact layer were p-type activated and a transparent electrode was crystallized by indirect resistance heating. This heat treatment was performed under a reduced pressure at a temperature of 700° C. Next, microwave heating was performed for three to thirty minutes at a temperature of 100° C. to 350° C. by microwave irradiation with a frequency of 5.8 GHz in a nitrogen atmosphere. This reduced a strain of the transparent electrode, and improved the conductivity or translucency of the transparent electrode.
1. A method for producing a semiconductor device having a transparent electrode on and in contact with a Group III nitride semiconductor layer, the method comprising:
forming the transparent electrode consisting of Zinc-doped Indium Oxide (IZO) on the Group III nitride semiconductor layer;
performing heat treatment at a first temperature by at least one of indirect resistance heating and infrared heating under an atmosphere containing nitrogen in a normal atmospheric pressure or a reduced pressure after the formation of the transparent electrode to crystallize the transparent electrode;
reducing a strain between the semiconductor layer and the transparent electrode by microwave heating under an atmosphere containing nitrogen at a second temperature after the heat treatment; and
performing another heat treatment at a third temperature by at least one of indirect resistance heating and infrared heating under an atmosphere containing oxygen to further crystallize the transparent electrode after the microwave heating,
wherein the microwave heating is performed at a second temperature in a range of 100° C. to 350° C. and lower than the first temperature.
2. The method for producing a semiconductor device according to claim 1 , wherein the first temperature is in a range of 600° C. to 800° C.
3. The method for producing a semiconductor device according to claim 1 , wherein the third temperature is in a range of 400° C. to 650° C.
4. The method for producing a semiconductor device according to claim 2 , wherein the third temperature is in a range of 400° C. to 650° C.