| 摘要 |
PURPOSE:To form a Pin structure easily on a multilayer films on a semi- insulating substrate without shallow control of the depth direction of P-type diffusion by a method wherein P-type regions are formed on an N<-> type InGaAs layer successively and periodically with the space between adjacent P-type regions about the width of a depletion layer when a reverse voltage is applied. CONSTITUTION:An N<-> type InP layer 8 with an N-type carrier concentration of about 1X10<16>cm<-3>, an N<-> type InP layer 9 with a carrier concentration of about 1X10<15>cm<-3> and an N<-> type InGaAs layer 10 with a carrier concentration of also about 1X10<15>cm<-3> are formed on a semi-insulating substrate 7. Then a comb-shape P-type region 11 is formed by ion implantation of Zn and a P-type electrode Au/Zn 12 and an N-type electrode 13 are formed. The mutual space l between the comb teeth of the P-type region 11 is about the width of a depletion layer which is expanded when a reverse voltage is applied. As carriers induced by an incident light perform as a diffusion current in the P-type region 11 and as a drifting current in the depletion layer region 20, excess carriers induced near the surface perform as the drifting current so that the influence of the rate-determination by the diffusion current can be reduced.
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