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:
Mar. 19, 1991
Filed:
Dec. 29, 1989
Keiji Takaoka, Yokohama, JP;
Tetsuo Sadamasa, Chigasaki, JP;
Motoyasu Morinaga, Yokohama, JP;
Nobuo Suzuki, Tokyo, JP;
Kenji Matsumoto, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
Disclosed are an avalanche photodiode and a manufacturing method thereof. An n.sup.- -type InGaAs light absorption layer and n.sup.- -type InP window layer are formed on an n-type InP substrate by crystal growth, in the order mentioned. A depression is formed in a selected surface portion of the window layer, and n-type impurities are doped into the bottom of the depression, to thereby form an n-type high concentration region. Further, n.sup.- -type crystal-grown InP layer is formed in the depression in such a way as to fill the depression. A guard ring is formed around the depression by the doping of p-type impurities. By doping p-type impurities into the window layer, a p-type high concentration region is formed in the window layer in a manner completely surrounding the interface between the n-type high concentration region and the crystal-grown InP layer. The n-type and p-type high concentration regions define a junction serving as a light-receiving region. Since the interface of the crystal-grown InP layer, which may not have a satisfactory crystalline structure, is located within the p-type high concentration regions, that interface is not supplied with a high electric field during use. Accordingly, the performance of the avalanche photodiode is not influenced by the interface.