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:
Jun. 23, 1998
Filed:
Jun. 01, 1995
Yoshihisa Fujisaki, Setagaya-ku, JP;
Yukio Takano, Musashimurayama, JP;
Tsutomu Ishiba, Kodaira, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
By exploiting an intense correlation exhibited between the distribution of lattice distortions in a wafer and the distribution of the threshold voltages of field effect transistors, the distribution of the lattice distortions in the wafer is reduced, thereby to mitigate the distribution of the characteristics of the semiconductor elements in the wafer. The difference between the maximum value and the minimum value of the lattice distortions of a GaAs single crystal at a normal temperature is set to at most 4.times.10.sup.-5, and the density of Si atoms contained in the GaAs single crystal is set to at most 1.times.10.sup.16 cm.sup.-3, whereby the characteristics of semiconductor elements whose parent material (substrate) is the GaAs single crystal can be made uniform.