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:
Aug. 03, 2021
Filed:
Sep. 07, 2017
Commissariat a L'energie Atomique ET Aux Energies Alternatives, Paris, FR;
Elénore Letty, Bourgoin Jallieu, FR;
Wilfried Favre, Chambery, FR;
Jordi Veirman, La Motte-Servolex, FR;
Abstract
A Czochralski-type method for sorting wafers obtained by cutting a single-crystal silicon ingot, the method being implemented when the wafers are in an as-cut state or in a shaped-surface state. The method includes a) measuring the majority free charge carrier concentration in an area of each wafer; calculating the thermal donor concentration in the area of each wafer, on the basis of the majority free charge carrier concentration; calculating the charge carrier lifetime limited by the thermal donors in the area of each wafer, on the basis of the thermal donor concentration; determining a bulk lifetime value for the charge carriers in each wafer on the basis of the lifetime limited by the thermal donors; comparing the bulk lifetime value or a normalised bulk lifetime value with a threshold value; and discarding the wafer when the bulk lifetime value or the normalised bulk lifetime value is lower than the threshold value.