Appeal No. 1998-1069
Application No. 08/259,575
providing a first gate structure and a second gate
structure on the oxide layer and overlying central portions of
the first and second wells, respectively;
performing a first LDD implant with ions of the first
conductivity type having an ion kinetic energies of at least
about 70 keV and having a first ion dose in the range of about
12 13 2
5 x 10 - 5 x 10 atoms/cm , said step of performing the first
LDD implant being conducted concurrently in the first and
second wells such that portions of the second well that do not
underlie the second gate structure are converted to first LDD
layers of the first conductivity type;
protecting the second well and the second gate structure
from ion implantation;
performing a second LDD implant with ions of the second
conductivity type having ion kinetic energies of at least
about 70 keV and having a second ion dose in the range of
about
12 14 2
7 x 10 - 5 x 10 atoms/cm , said step of performing the
second LDD implant being conducted in the first well such that
portions of the first well that do not underlie the first gate
structure are converted to second LDD layers of the second
conductivity type; and
performing separate implants in the first and second
wells with ions having ion kinetic energies in the range 40 -
15 16
180 keV and having an ion does in the range 10 - 10
atoms/cm to form completed sources and drains in the first2
and second wells.
The Examiner relies on the following references:
Schwabe et al. (Schwabe) 4,525,378 Jun.
25, 1985
Hsu et al. (Hsu) 4,927,777 May 22,
1990
4
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