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:
Jan. 31, 1989
Filed:
Jan. 14, 1987
Motorola, Inc., Schaumburg, IL (US);
Abstract
A process for forming graded source/drain regions in semiconductor devices involves two ion implantation steps and an optional drive-in step. The first implantation is a low dose implant with high energy and/or low mass ions to form the deeper grading region. The second implant is a high does implant with low energy and/or high mass ions to form the shallower, lower resistivity source/drain region. Without the optional drive-in step, virtually no lateral grading takes place, resulting in little encroachment of the grading region under the gate. The use of a drive-in step between the two implant steps causes diffusion of the grading dopant, which increases the grading both laterally and vertically, resulting in better breakdown and capacitance characteristics, but increased encroachment under the gate. The present invention allows control over the lateral and vertical grading separately to optimize the trade-offs for a particular application.