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:
Dec. 29, 1998
Filed:
May. 28, 1997
Masao Kunitou, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A semiconductor read only memory device has a p-type contact region nested in a p-type drain region of a p-channel type field effect transistor and formed through a first ion-implantation of boron through a first opening of a photo-resist mask and a first contact hole of an inter-level insulating layer under a first acceleration energy too small to penetrate the inter-level insulating layer and a channel region of a memory transistor formed in a p-type well and formed through a second ion-implantation of phosphorous through a second opening of the photo-resist mask and the inter-level insulating layer under a second acceleration energy too large to stop the phosphorous in the p-type drain region so that the photo-resist mask is shared between the two ion-implantations.