CMOS integrated circuit having a sacrificial metal spacer for producing graded NMOS source/drain junctions dissimilar from PMOS source/drain junctions
First Claim
1. A method for forming a CMOS integrated circuit, comprising:
- patterning a first gate conductor between opposing sidewall surfaces across a first channel portion of a semiconductor topography;
using the first gate conductor as a mask, implanting a first n-type dopant into said semiconductor topography adjacent said channel portion;
forming a dielectric spacer upon the sidewall surfaces;
using the dielectric spacer and the first gate conductor as a mask, implanting a second n-type dopant into said semiconductor topography a first spaced distance from said channel portion;
forming a conductive spacer upon the dielectric spacer; and
using the conductive spacer, the dielectric spacer and the first gate conductor as a mask, implanting a third n-type dopant into said semiconductor topography a second spaced distance greater than the first spaced distance from said channel portion.
0 Assignments
0 Petitions
Accused Products
Abstract
An integrated circuit is formed whereby junction of NMOS transistors are formed dissimilar to junctions of PMOS transistors. The NMOS transistors include an LDD area, an MDD area and a heavy concentration source/drain area. Conversely, the PMOS transistor include an LDD area and a source/drain area. The NMOS transistor junction is formed dissimilar from the PMOS transistor junction to take into account the less mobile nature of the junction dopants relative to the PMOS dopants. Thus, a lessening of the LDD area and the inclusion of an MDD area provide lower source/drain resistance and higher ohmic connectivity in the NMOS device. The PMOS junction includes a relatively large LDD area so as to draw the highly mobile, heavy concentration boron atoms away from the PMOS channel.
-
Citations
20 Claims
-
1. A method for forming a CMOS integrated circuit, comprising:
-
patterning a first gate conductor between opposing sidewall surfaces across a first channel portion of a semiconductor topography; using the first gate conductor as a mask, implanting a first n-type dopant into said semiconductor topography adjacent said channel portion; forming a dielectric spacer upon the sidewall surfaces; using the dielectric spacer and the first gate conductor as a mask, implanting a second n-type dopant into said semiconductor topography a first spaced distance from said channel portion; forming a conductive spacer upon the dielectric spacer; and using the conductive spacer, the dielectric spacer and the first gate conductor as a mask, implanting a third n-type dopant into said semiconductor topography a second spaced distance greater than the first spaced distance from said channel portion. - View Dependent Claims (2, 3, 4, 5, 6, 11, 12, 13, 14, 15)
-
-
7. A method for forming an integrated circuit, comprising:
-
patterning a first gate conductor having opposed sidewall surfaces across a first channel portion of a dielectric covered semiconductor substrate; forming a dielectric spacer upon the sidewall surfaces and a conductive spacer upon the dielectric spacer; using the conductive spacer, the dielectric spacer and the gate conductor as a mask, implanting into said semiconductor substrate n-type dopants at a first concentration; using the dielectric spacer as an etch stop, removing the conductive spacer; using the dielectric spacer and the gate conductor as a mask, implanting into said semiconductor substrate n-type dopants at a second concentration less than the first concentration; using the gate conductor as an etch stop, removing the dielectric spacer; and using the gate conductor as a mask, implanting into said semiconductor substrate n-type dopants at a third concentration less than the second concentration. - View Dependent Claims (8, 9, 10, 16, 17, 18, 19, 20)
-
Specification