JPS6442182A - Manufacture of photodiode - Google Patents

Abstract

PURPOSE:To make the diffusion depth of a diffused layer small and obtain a high relative sensitivity on a shorter wavelength side by a method wherein the surfaces of diffused layers for forming a p-n junction are selectively oxidized and selectively oxidized oxide films are removed by etching with etchant such as HF. CONSTITUTION:An n<+>type buried layer 4, p-type buried layers 2 and an n-type epitaxial layer 3 are formed on a substrate 1. Field oxide films 5 are formed on required parts above the n-type epitaxial layer 3 and the p-type buried layers 2. An n<+>type diffused layer 7 and isolating diffused layers 6 are formed in the parts covered with nitride films at the time of field oxidization and, with the same diffusion process, a base diffused layer 9 is formed on the required part of the surface of the n-type epitaxial layer 3. Then a nitride film 10 is formed and patterned to form an aperture on the surface 8 of a photodiode. After oxidization, the nitride film is removed and a thick oxide film 11 on the photodiode surface is etched with etchant such as HF. With this constitution, as the thicknesses of the diffused layers for forming the p-n junction of the photodiode are reduced, a photodiode with excellent spectral characteristics of shorter wavelength side can be obtained.