| 摘要 |
PURPOSE:To form the semiconductor photo detector having no variation of the characteristic even in high temperature environment by a method wherein a P type ohmic electrode is formed with an eutectic alloy formed according to combination of a metal to form an eutectic alloy to the semiconductor crystal of the photo detecting part and a semiconductor the same kind with the semiconductor crystal. CONSTITUTION:Boron ion implantation and an annealing treatment are performed to N type germanium (carrier concentration is 5X10<15>cm<-3>) 1, and the P<+> type layer (carrier concentration is 1X10<18>cm<-3>) is formed at 0.3mum thickness to be used as the photo detecting layer 2. Moreover both the edges of the photo detecting layer 2 are converted locally into the P type (carrier concentration 5X10<17>cm<-3>) according to diffusion of zinc, and a guard ring of 3mum thickness is formed. At this time, an SiO2 layer 4 used for selective diffusion is used as the insulating material of the electrode 5. The electrode 5 is obtained by evaporating locally the alloy of aluminum 30% and germanium 70%, and moreover the favorable ohmic characteristic can be obtained according to the proper annealing treatment. Because the distance of an N type electrode 6 up to the P-N junction part is far, ohmic contact is provided by the usual method, by the alloy of gold/ antimony for example. |
