ZINC SOLID PHASE DIFFUSION METHOD OF INDIUM PHOSPHIDE (InP) SYSTEM LIGHT RECEIVING ELEMENT AND INDIUM PHOSPHIDE SYSTEM LIGHT RECEIVING ELEMENT

摘要

PPROBLEM TO BE SOLVED: To solve the problem that zinc is to be doped for forming a p-region in an InP system light receiving element; that it is difficult to perform a closed tube method in the case of a large InP wafer in trend of practical use although zinc is doped by gaseous phase diffusion with the closed tube method in the case of a small InP wafer; and that SiN of a mask is removed when a ZnO thin film is removed by hydrofluoric acid after zinc is diffused, a pn junction end is exposed, pn junction is deteriorated, a defect and dislocation occur, and leak current and dark current increase since a solid phase diffusion method is desired for attaching the ZnO thin film to an epitaxial wafer, heating it and diffusing zinc from the ZnO thin film to an InP epitaxial layer. PSOLUTION: The mask where a-Si is set to be an upper layer is used as a diffusion mask. Since a-Si does not melt in hydrofluoric acid, a-Si does not melt and is maintained as it is when ZnO is removed by hydrofluoric acid. Since a-Si film remains, a pn bonding end is not exposed. The diffusion mask always covers the pn bonding end as a protection film. Thus, pn bonding is not deteriorated. PCOPYRIGHT: (C)2006,JPO&NCIPI