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. 15, 1999
Filed:
Dec. 01, 1997
David K Liu, Fremont, CA (US);
Kou-Su Chen, Fremont, CA (US);
AMIC Technology, Inc., Santa Clara, CA (US);
Abstract
A test circuit for observing charge retention characteristics of cells in a flash memory array is disclosed. Unlike prior art structures, the present circuit monitors both charge loss and charge gain of cells in the array. In this way, cells having conduction thresholds below a desired target threshold and cells having conduction thresholds above a desired target threshold can both be observed. The circuit includes a regular memory array, and a mirror array formed with devices having opposite channel types to the regular array. By identifying and evaluating more accurately the threshold characteristics of a particular cell design or cell process, improvements can be made to such designs and processes in a more rapid and optimal fashion.