| 摘要 |
PURPOSE:To keep the thickness of an opening part of a doped AlyIn1-yAs layer constant with high accuracy by etching a GaxIn1-xAs layer formed on an AlyIn1-yAs layer by a mixed solution of KOH and H2O2. CONSTITUTION:A doped AlyIn1-yAs layer 12 is that of 400Angstrom thickness, 10<18>cm<-3> impurity concentration, and mixed crystal rate y=0.52. A doped GaxIn1-xAs layer 16 is that of 600Angstrom thickness. 10<19>cm<-3> impurity concentration, and mixed crystal rate x=0.53. On the doped GaxIn1-xAs layer 16, an SiO2 film 17 is grown to 3,000Angstrom by CVD technique and an opening of 1mum width is formed on the SiO2 film 17 by using a resist. As an etchant, KOH (5wt% water solution) and H2O2 are mixed by volume ratio 20:1, after which an epitaxial wafer comprising a hetero junction is immersed in the etchant. Consequently, because an etching rate of GaxIn1-xAs is several times an etching rate of AlyIn1-yAs, an etching rate diminishes abruptly when the AlyIn1-yAs comes to the surface, and the control of an etching time becomes easy.
|
