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. 20, 1989
Filed:
May. 20, 1988
Helmut Foell, Munich, DE;
Volker Lehmann, Munich, DE;
Siemens Aktiengesellschaft, Berlin and Munich, DE;
Abstract
Method and measuring instrument for identifying the diffusion length of minority charge carriers for non-destructive detection of flaws and impurities in semiconductor crystal bodies. The method provides that the semiconductor crystal body is positioned between two electrolyte-filled measuring chamber halves and that the minority charge carriers of the photocurrent that results at a front side of the semiconductor crystal body due to irradiation is detected by an applied constant voltage between a backside of the semiconductor crystal body and a rear electrolyte at the backside of the semiconductor crystal body. Taking the thickness (D) of the semiconductor crystal body into consideration, the diffusion length (L) can be calculated from a mathematical equation using the quotient of the minority charge carrier current I.sub.G I/.sub.O occurring at the backside and at the front side of the semiconductor crystal body. The method provides topically resolved measurements for irradiation of the semiconductor crystal body. A measuring instrument for the implementation of the method is disclosed. The method can be used for determining the quality of semiconductor crystals.