| 摘要 |
PURPOSE:To form a high-luminous output and short-wavelength semiconductor laser without increasing the series resistance by making an impurity diffuse in the clad layer in such a way that the carrier density in the vicinity of the active layer becomes smaller. CONSTITUTION:The temperature of the substrate is made to rise for about 20hr up to reach 70 deg.C, then Al and Ga are respectively irradiated at 1,100 deg.C and 950 deg.C for forming the N type clad layer. At this time, Sn is diffused first as an impurity at 850 deg.C at the same time as the time the Al and Ga are irradiated. In such the state, the irradiation of Al and Ga is performed and when the prescribed time, when is required by the time the N type clad layer is formed and reaches the vicinity of the active layer, elapses to the clad layer to be formed, the first diffusion temperature of Sn is lowered to 750 deg.C. In this state, the impurity Sn is diffused throughout the prescribed time to be required by the time the N type clad layer is formed. When the N type clad layer is formed, the GaAs active layer is formed. Then, the P type clad layer is formed. In this case, Be is diffused as an impurity at temperatures of 800 deg.C or thereabouts. Furthermore, the gap layer is formed. In this case, the temperature for the formation of the gap layer is set at 850 deg.C, though the impurity Be keeps being diffused.
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