The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 18, 2010
Filed:
Apr. 15, 2008
Eiji Yagyu, Tokyo, JP;
Eitaro Ishimura, Tokyo, JP;
Masaharu Nakaji, Tokyo, JP;
Mitsubishi Electric Corporation, Tokyo, JP;
Abstract
A semiconductor light-receiving device and its manufacturing method are provided which are capable of suppressing dark current and deterioration. Semiconductor crystals were sequentially grown over an n-type InP substrate, including an n-type InP buffer layer, an undoped GaInAs light absorption layer, an undoped InP diffusion buffer layer, and a p-type InP window layer. Next, a first mesa was formed by removing a part from the p-type InP window layer to the n-type InP buffer layer with a Br-based etchant having low etching selectivity, so as to form a sloped 'normal' mesa structure. Next, a second mesa having a smaller diameter than the first mesa was formed by dry etching, by precisely removing a part from the p-type InP window layer to a certain mid position of the undoped InP diffusion buffer layer.