| 摘要 |
PURPOSE:To execute effective confinement of light by forming a striped SiO2 film on a waveguide layer thus forming an optical waveguide having an effective stage difference of refractive index to that of a direction parallel to a boundary face. CONSTITUTION:A ZnS layer functioning as a lower clad layer is formed by an epitaxial growth by an MOCVD method on a GaAs substrate, then an SiO2 mask 5 is deposited by a thermal CVD method. Then, the SiO2 film is patterned and the SiO2 film at the part for forming a waveguide layer is removed. A ZnSe layer for a waveguide layer and a ZnS layer for a clad layer are formed successively by a selective epitaxial growth using the patterned SiO2 film. In this stage, there is no deposit on the masking SiO2 film. For the selective epitaxial growth of ZnS and ZnSe, org. compds. of Zn, S, and Se are used as raw materials, and the pressure is regulated to <=100Torr, the temp. to >=400 deg.C and <=700 deg.C, and a molar ratio of a VI group raw material and a II group to be fed to <=6, by a reduced pressure MOCVD method. Thus, a ZnSe layer for a waveguide layer and ZnS layer for a clad layer are formed. An optical waveguide is completed by removing SiO2 with HF. |
