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:
Mar. 14, 1989
Filed:
Aug. 26, 1987
Huntington W Curtis, Chelsea, NY (US);
Min-Su Fung, LaGrangeville, NY (US);
Roger L Verkuil, Wappingers Falls, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A contactless technique for semiconductor wafer testing comprising: depositing charges on the top surface of an insulator layer over the wafer to create an inverted surface with a depletion region and thereby a field-induced junction therebelow in the wafer, with an accumulated guard ring on the semiconductor surface therearound. The technique further includes the step of changing the depth to which the depletion region extends below the inverted semiconductor wafer surface to create a surface potential transient, and the step of measuring a parameter of the resultant surface potential transient. This technique may be utilized to make time retention and epi doping concentration measurements. It is especially advantageous for reducing the effects of surface leakage on these measurements. In a preferred embodiment, corona discharges are used to effect the charge deposition configuration. Either corona discharge or photon injection are used to change the depletion region depth.