| 摘要 |
PURPOSE:To realize high speed and obtain a photo detector having excellent characteristics for use in optical communication, by forming a layer showing the reverse conductive type to that of substrate on the surface of a semiconductor substrate, and removing the substrate beneath the light entrance plane. CONSTITUTION:A P<-> type Si layer 2 reverse to substrate is formed on N<+> type Si substrate 1 by epitaxial growth and phosphorus is selectively diffused thermally by using a thermally oxidizing SiO2 film, and N<+> type Si layer 3 and phosphorus are similarly ion-injected and an N type Si layer 4 is formed by thermal diffusion. Using a silane compound having such a thickness that does not cause reflection to the wavelength of incident light, a layer is formed with Si2N4 film 7 by CVD. In order to shield the light from entering from the outside of the upper part of PN junction plane, an aluminum vapor deposition film 9 is provided, and the substrate is selectively removed by etching by using the thermally oxidized SiO2 film. Then, boron is thermally diffused at impurity concentration to form a P+ type Si layer 10. The incident light passing this layer is reflected by an Au film 11. |
