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. 20, 1990
Filed:
Mar. 21, 1989
Akira Takemoto, Itami, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A semiconductor laser device of the buried heterostructure type in which leakage current is substantially reduced. A mesa portion carries the active lasing portion of the laser, and current blocking layers are grown at either side of the mesa portion. One of the current blocking layers has its conductivity type inverted to the opposite type to eliminate a current leakage path, thereby to provide a high efficiency low leakage current semiconductor laser. Conductivity inversion is accomplished by adjusting the impurity concentration levels in the layers on either side of the mesa portion, and controllably diffusing impurities from one layer to another until conductivity inversion is accomplished in a thin tip portion of one of the layers.