avalanche photodiode

Abstract

Abstract PURPOSE:To enable the APD having a uniform multiplying region to be obtained by a method wherein the impurity concentration at the center of the first conductivity type region of high concentration is made higher than that in the periphery of this first conductivity type region. CONSTITUTION:The breakdown voltage of both the center of the high concentration region and its periphery is made to have a difference by having a difference in impurity concentration. This difference in withstand voltage can be arbitrary taken according to states of formation of said high concentration region. The method of forming the high concentration region includes: (1) formation by ion implantation after a recess is bored in the substrate by etching, and by heat treatment thereafter and surface etching; (2) formation by setting the injection dosage at a desired value by variation in thickness of a selective injection mask, and thereafter by heat treatment; (3) formation by many times of selective ion implantation and heat treatment thereafter. Then, a P<+> region is formed, and a guard ring is formed if not formed into an element structure. Thus, a distribution of impurity concentration where there is some difference in impurity concentration between the center and the periphery in the region 18, leading to uniform multiplication is formed.

Inventors

• 👤 Masaru Niwa
• 👤 丹羽　勝

Bibliographic Details