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:
Nov. 20, 1990
Filed:
Mar. 22, 1989
National Space Development Agency of Japan, both of, JP;
Foundation for Advancement of International Science, both of, JP;
Abstract
An intermediate layer made of an Si.sub.1-X Ge.sub.X mixed crystal layer is formed on an Si crystal substrate, where the character X denotes a value in the range of 0 to 1. The intermediate layer is connected to the substrate via a heterojunction generating a first heterojunction barrier. An Si crystal layer is formed on the intermediate layer and is connected to the intermediate layer via a heterojunction generating a second heterojunction barrier. The substrate, the intermediate layer, and the Si layer form a laminated structure. The first and second heterojunction barriers form a charge storage well in an energy band of the intermediate layer. Charges in the well are excited by absorbing infrared light. The intermediate layer contains unevenly-distributed impurities whose concentration montonically varies in a direction along a thickness of the laminated structure. The variation in the concentration generates an internal electric field in the energy band of the intermediate layer. The internal electric field increases a probability of movement of the excited charges from the well into one of the substrate and the Si layer.