Forming method for guard ring of avalanche photodiode

Abstract

Abstract PURPOSE:To form a guard ring by a low concentration Cd diffusion layer simply and positively by a mechanism wherein Cd is diffused to the desired region of a semiconductor in III-V group compounds in the periodic table, a mask is made up and thermal diffusion is conducted. CONSTITUTION:An N type InGaAs semiconductor layer 22 is formed on an N type InP semiconductor layer 21, an SiO2 film 23 is further deposited, diffusion holes 24 are built up to the guard ring forming prearranged sections of the film 23, Cd is diffused from the holes 24, and high concentration Cd layers 25 are made up. an SiO2 mask 26 is deposited on the film 23 to clog the holes 24, and thermal diffusion is conducted and a low concentration Cd diffusion layer is built up. The film 23 and the mask 26 are selectively etched, and a P<+> layer 28 is formed. Thus, the low stable characteristics of dark currents are obtained because the breakdown voltage of junction made up by a guard ring 27 and the layer 22 is sufficiently greater than that of the junction built up by the layers 28 and 22 in the obtd. avalanche photodiode acquired.

Inventors

• 👤 Hiroaki Ando
• 👤 Yoshihisa Yamamoto

Bibliographic Details