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. 14, 2002
Filed:
Jun. 16, 2000
Showa Denko Kabushiki Kaisha, Tokyo, JP;
Abstract
The present invention provides an epitaxial wafer which is obtained by sequentially forming, on an n-type GaAs substrate, a first n-type GaAlAs layer; a second n-type GaAlAs layer; an n-type GaAlAs cladding layer; a p-type GaAlAs active layer which has an emission wavelength of 850-900 nm; and a p-type GaAlAs cladding layer, through liquid phase epitaxy, and, subsequently, removing the n-type GaAs substrate. In the epitaxial wafer, the p-type GaAlAs cladding layer has a thickness of 5-30 &mgr;m; the p-type GaAlAs cladding layer has an oxygen concentration of 3×10 atoms/cm or less; the p-type GaAlAs cladding layer has a carrier concentration of 1×10 cm to 1×10 cm ; the p-type GaAlAs active layer has a thickness of 0.05-0.4 &mgr;m; the peak carbon concentration of the portion in the second n-type GaAlAs layer within 2 &mgr;m of the interface between the second n-type GaAlAs layer and the first n-type GaAlAs layer is less than 1×10 atoms/cm ; the p-type GaAlAs active layer contains germanium as a predominant dopant; the n-type GaAlAs cladding layer has a Ge concentration of 3×10 atoms/cm or less; and the second n-type GaAlAs layer has a Ge concentration of 3×10 atoms/cm or less. The invention provides an epitaxial wafer of double-hetero structure for producing high-intensity GaAlAs infrared LEDs.