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. 04, 2000
Filed:
Dec. 11, 1997
Richard A Chapman, Dallas, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A process for forming high voltage and low voltage transistors on the same substrates includes first forming a poly gate (16) over layer gate oxide (10) on a substrate (12). An LDD implant is then performed, followed by the formation of a nitride cap (30) over the gate (16). The cap (30) is not disposed over gate electrodes associated with low voltage transistors. Thereafter, the source/drain implant is performed which forms source/drain regions (40) and (42). The cap (30) prevents the introduction of dopants into the gate electrode (16) during the source/drain implant step. This effectively increases the gate oxide width due to a larger depletion region at the oxide/polysilicon gate boundary as compared to the low voltage transistors with the higher dopant levels and the gate electrode.