Method for using thin spacers and oxidation in gate oxides
AssigneeMicron Technology, Inc.
InventorsSalman Akram, Mohamed A. Ditali
Life of this patent
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Abstract
A method for forming a lightly doped drain (LDD) field effect transistor uses very thin first sidewall spacers over the gate sidewalls, in which annealing/oxidation of the sidewall spacers results in (a) the rounding of corner portions of the gate structure sidewalls adjacent the gate oxide, and (b) a very low thermal consumption comprising a small portion of the total thermal budget. Secondary sidewall spacers of greater width are then formed to act as offsets in the introduction of N-type dopants into the substrate to form source and drain contact regions. The method may be varied to accommodate various design configurations and size scaling.
Claims5
A manufacturing method for a transistor on a substrate, comprising:
- providing a substrate having a dielectric layer thereon;
- forming a gate structure on said dielectric layer having a gate oxide layer formed on said dielectric layer and a metal suicide layer formed on said gate oxide layer, said gate structure having a first sidewall and a second sidewall, said first sidewall and said second sidewall defining therebetween within said substrate a first contact region, a channel region and a second contact region;
- and
- forming first, second, and third subregions within said second contact region, each subregion having a dopant concentration that differs from that of the other two subregions, said forming of said first, second, and third subregions comprising:
- depositing a conformal layer of dielectric material over said substrate;
- anisotropically etching said conformal layer of dielectric material, forming a layer of dielectric material on said first sidewall and said second sidewall;
- subjecting said layer of dielectric material on said first sidewall and said second sidewall to an annealing/oxidation process;
- forming a single layer sidewall spacer overlying said first sidewall and said second sidewall;
- introducing a first dopant into said substrate to form said first subregion;
- forming another single layer sidewall spacer overlying said single layer sidewall spacer;
- introducing a second dopant into said substrate to form said second subregion;
- substantially removing said another single layer sidewall spacer;
- and
- introducing a third dopant into said substrate to form said third subregion.
Dependencies are inferred from the claim text.