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:
Oct. 20, 1998
Filed:
Dec. 10, 1996
Jun Muramoto, Kyoto, JP;
Rohm Co., Ltd., Kyoto, JP;
Abstract
Pulse shaped voltage of 5V is applied to a source region 3 at initial phase of erase by a pull back voltage generator 13 connected to the sources region 3. Then, the pulse shaped voltages of 10V and 12V increased under stepwise bases are applied to source region 3 with progress of erasion. Generation of hot-holes at the initial phase of data erasion can be prevented because difference in voltage between the floating gate electrode 5 and source region 3 is decreased. Value of the pulse shaped voltage thus applied is increased for the difference occurred between the floating gate electrode 5 and source region 3 when erasion is in much progress. Thus, it is possible to pull out the stored electrons from the floating gate electrode 5 until the threshold voltages can be set at predetermined values. So that, degradation of characteristics of a gate oxidation layer caused by hot-holes generated with erasion can be prevented.