Semiconductor device manufacturing: process – Making field effect device having pair of active regions... – Having insulated gate
Reexamination Certificate
2001-06-20
2002-08-06
Lebentritt, Micheal S. (Department: 2824)
Semiconductor device manufacturing: process
Making field effect device having pair of active regions...
Having insulated gate
C438S300000, C438S424000, C438S479000, C438S589000
Reexamination Certificate
active
06429084
ABSTRACT:
FIELD OF THE INVENTION
The field of the invention is submicron MOS circuit processing with raised source/drain structures.
BACKGROUND OF THE INVENTION
In forming raised source-drain (S/D) transistors in submicron dimensions, a problem has arisen—that the polysilicon (poly) gate acts as a base for epitaxial growth as well as the exposed silicon in the S/D region. The epitaxial silicon (epi) in the gate expands laterally and not only physically blocks portions of the S/D, but also causes variation in device characteristics along the length of the transistor because of interference between the expanded gate and the S/D extension implant.
In addition, the preclean step that is required to remove oxide before the epi growth can overetch the shallow trench isolation (STI) fill, exposing silicon during the epi growth step. With this unwanted epi at or near the isolation, there is a potential for shorting across the isolation.
SUMMARY OF THE INVENTION
The invention relates to a method of transistor formation that provides a protective layer over the gate and over the STI during the epi growth step, thereby preventing unwanted epi growth on the gate and/or in the isolation.
A feature of the invention is the formation of temporary poly sidewalls that are removed before the S/D implantation, so that the extension and/or halo implants are performed after the S/D implant, and preferably after the S/D anneal.
Another feature of the invention is forming an oxide
itride/oxide sandwich layer on top of the poly so the poly top surface is not exposed during the removal of the temporary poly sidewall spacer.
Yet another feature of the invention is damaging the protective layer by ion implantation before its removal.
REFERENCES:
patent: 5493575 (1996-02-01), Kitamura
patent: 5943581 (1999-08-01), Lu et al.
patent: 6127228 (2000-10-01), Lee
patent: 6204138 (2001-03-01), Krishnan et al.
patent: 6204532 (2001-03-01), Gambino et al.
patent: 6223432 (2001-05-01), Dennison et al.
patent: 6274913 (2001-08-01), Brigham et al.
patent: 6300657 (2001-10-01), Bryant et al.
patent: 6326262 (2001-12-01), Temmler et al.
patent: 2001/0044188 (2001-11-01), Heo et al.
patent: 2002/0011617 (2002-01-01), Kubo et al.
Assaderaghi Fariborz
Park Heemyong
Schepis Dominic J.
Anderson Jay H.
Lebentritt Micheal S.
LandOfFree
MOS transistors with raised sources and drains does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with MOS transistors with raised sources and drains, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and MOS transistors with raised sources and drains will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2917577