| 摘要 |
PURPOSE:To permit ohmic contact of an epitaxial wafer, consisting of an epitaxial wafer for a light emitting diode having a low surface carrier concentration, or the epitaxial wafer consisting of GaAlAs having a high surface mix crystal ratio, stably, the evaluation of the light emitting characteristics of the wafer under the condition of wafer as it is, and the evaluation of light emitting characteristics even in a big current area. CONSTITUTION:A diffusion source 14 of impurity adding oxide type is coated on the surface of a p-type GaAs epitaxial layer 3 and the layer 3 is baked under a predetermined heat treating condition. Solid phase-solid phase diffusion is effected under a temperature condition, capable of obtaining a desired carrier concentration and a diffusion depth, to form a diffusion layer 4. A small area 6, surrounded by a groove 5, is formed on the surface of the epitaxial wafer, on which the solid phase-solid phase diffusion is applied, to isolate the small area 6 from the other area 7 electrically. The light emitting characteristics of the epitaxial wafer is evaluated by a probing method wherein an electric needle 8 is pierced into the diffusion layer 4 of the small area 6 to conduct an electric current therethrough. |
