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:
Oct. 21, 2014
Filed:
Dec. 22, 2010
Naoki Tamari, Tsukuba, JP;
Toru Kinoshita, Tsukuba, JP;
Naoki Tamari, Tsukuba, JP;
Toru Kinoshita, Tsukuba, JP;
Tokuyama Corporation, Yamaguchi, JP;
Abstract
A method for forming an n-type contact electrode, which includes an n-type nitride semiconductor such as AlInGaN (with x, y, and z being rational numbers that sum to 1.0 and fulfill the relations 0<x≦1.0, 0≦y≦0.1, and 0≦z<1.0), includes: a step in which a first electrode metal layer including at least one metal selected from titanium, vanadium, and tantalum is formed on a layer of the aforementioned n-type semiconductor and then heat-treated at a temperature between 800° C. and 1200° C.; and a step in which a second electrode metal layer is formed on top of the first electrode metal layer and then heat-treated at a temperature between 700° C. and 1000° C. The second electrode metal layer contains a layer comprising a metal, such as aluminum, that has a work function between 4.0 and 4.8 eV and a resistivity between 1.5×10Ω·cm and 4.0×10Ω·cm.