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:
Jul. 05, 2005
Filed:
Apr. 28, 2003
Koji Ebara, Annaka, JP;
Koji Ebara, Annaka, JP;
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
The present invention is to provide a method for measuring resistivity of a semiconductor wafer by the use of an AC-SPV method even though the wafer is left in a depletion state or a weak inversion state. The present invention is the method for measuring resistivity of a semiconductor wafer by the use of a surface photo voltage method, and comprises the steps of: (a) measuring a surface photo voltage value in both regions of a low frequency region in which a constant surface photo voltage value is obtained irrespective of a frequency of incident light on a semiconductor wafer to be measured and in a high frequency region in which the surface photo voltage value inversely proportional to the frequency of the incident light is obtained and calculating a cut-off frequency ffrom the obtained measured value; (b) calculating a depletion layer width Wfrom capacitance Ccalculated from the surface photo voltage value in the high frequency region; (c) calculating majority carrier conductance gfrom the cut-off frequency fand the capacitance C; and (d) calculating surface potential Uand Fermi potential Ufrom the cut-off frequency f, the capacitance C, the depletion layer width W, and the majority carrier conductance g.