| 摘要 |
PURPOSE:To execute confinement of light effectively by using an optical waveguide having a ridge type waveguide layer and a waveguide covered completely with a thin dielectric film. CONSTITUTION:A ZnS layer functioning as a lower clad layer is formed on a GaAs substrate by an epitaxial growth in accordance with MOCVD method, then SiO2 is deposited as mask 5 by a thermal CVD method, etc. Then, the SiO2 mask is patterned by a photolithographic technique. In this case, the SiO2 film at a part for forming a waveguide layer is removed by etching. Then, a waveguide layer comprising ZnSe is formed by a selective epitaxial growth method using the patterned SiO2 as mask. Org. compds. of Zn and Se are used as raw materials, and the selective epitaxial growth is proceeded by regulating a growth pressure to <=100Torr, a growth temp. to >=400 deg.C and <=700 deg.C, and a molar ratio of a VI group raw material to a II group raw material to be fed to <=6, by a reduced pressure MOCVD method, etc. After forming ZnSe which serves as a waveguide layer, the SiO2 film is removed with an HF type etchant. Thus, an SiO2 film is formed so as to cover the whole ZnSe surface. |
