| 摘要 |
PURPOSE:To prevent the edge breakdown at the junction terminal, to reduce the dark current and to obtain the avalanche photodiode with which high multiplication can be obtained by a method wherein a guard ring is formed by diffusing Zn at a low temperature. CONSTITUTION:An N type InxGa1-xAsyP1-y (0<=x<=1, 0<=y<=1) semiconductor layer 25, which will be buried later, is formed on an N<+> type InP semiconductor layer 26 by performing an epitaxial growth, and then an N type InP semiconductor layer 8', which forms the heterojunction with the semiconductor layer 25, is formed. Then the deep P-N junction 16 of the guard ring 11 is formed by performing a low temperature diffusion at the temperature of 500 deg.C or below of Zn, and a P<+> type InP semiconductor layer 10' and a shallow P-N junction 17, which will be used to detect light 24, are formed using Zn or Cd. Besides, numeral 12 in the diagram represents an insulating film and numerals 14 and 15 represent an electrode. This device is constituted in such a manner that one end of depletion layer exists in the semiconductor layer 25 when voltage is applied to the P-N junction so that an avalanche multiplication can be generated. |
