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Twin Well Sub-0.25mm CMOS with Ultra-shallow Junction Fabricated Using a Selective Epitaxial Technique

IP.com Disclosure Number: IPCOM000109662D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 3 page(s) / 80K

Publishing Venue

IBM

Related People

Hsu, CH: AUTHOR [+2]

Abstract

Disclosed is a method to fabricate sub-0.25 mm CMOS devices with ultra-shallow junction using a selective epitaxial technique. This method decouples the channel doping profile from the doping profile of a punch-through stopper and provides a junction shallower than 50 nm, which is indispensable for sub-0.25 mm CMOS technology.

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Twin Well Sub-0.25mm CMOS with Ultra-shallow Junction Fabricated Using a Selective Epitaxial Technique

       Disclosed is a method to fabricate sub-0.25 mm CMOS
devices with ultra-shallow junction using a selective epitaxial
technique.  This method decouples the channel doping profile from the
doping profile of a punch-through stopper and provides a junction
shallower than 50 nm, which is indispensable for sub-0.25 mm CMOS
technology.

      As the density of CMOS circuit increases, the device size has
to be shrunk.  The scaled CMOS devices inherit dramatical short
channel effect and punch-through if the junction and channel doping
profiles are not designed appropriately.  Using a conventional
profile tailoring technique by implantation, the punch-through stop
implant would affect the threshold voltage significantly for a device
with a ultra-shallow junction.

      The present invention serves to decouple the channel profile
(which determines the threshold voltage) from the profile of
punch-through stopper using selective epitaxial technique.  Using
this method can (1) form an ultra-shallow junction from tailoring the
junction profile by the profile of punch-through stopper, (2) obtain
source/drain extension without extra masks, and (3) accomplish an
isolation structure without the disadvantages of bird's  beak due to
nitride capped thermal reoxidation and parasitic leakage due to
defects in the trench isolation.  Since the surface concentration is
low,...