Patents by Inventor Yoshinobu Tsujikawa

Yoshinobu Tsujikawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Epitaxial wafer for use in the production of an infrared LED
    Patent number: 4575742
    Abstract: The present invention relates to a wafer for use in the production of an infrared LED. Conventionally, infrared LEDs are produced by using an epitaxial wafer comprising P- and N-type GaAs epitaxial layers. The wafer according to the present invention is characterized by having a P-type Ga.sub.1-x Al.sub.x As epitaxial layer and improves the output power of infrared LEDs. The epitaxial layers according to the present invention are (1) a 20-100 .mu.m thick N-type GaAs epitaxial layer consisting of N-type GaAs doped with Si and having a carrier concentration in the range of from 1.0.times.10.sup.17.cm.sup.-3 to 2.0.times.10.sup.18.cm.sup.-3, (2) a 10-80 .mu.m thick P-type GaAs epitaxial layer consisting of P-type GaAs doped with Si and having a carrier concentration in the range of from 1.0.times.10.sup.17.cm.sup.-3 to 5.0.times.10.sup.18.cm.sup.-3, and (3) a 5-90 .mu.m thick mixed crystal layer consisting of P-type Ga.sub.1-x Al.sub.x As mixed crystal and having a carrier concentration of from 1.0.times.10.sup.
    Type: Grant
    Filed: December 27, 1983
    Date of Patent: March 11, 1986
    Assignee: Mitsubishi Monsanto Chemical Co., Ltd.
    Inventors: Yasuji Kohashi, Yoshinobu Tsujikawa