US 8,298,925 B2 · Mechanisms for forming ultra shallow junction

Abstract

The embodiments of methods and structures are for doping fin structures by plasma doping processes to enable formation of shallow lightly doped source and drain (LDD) regions. The methods involve a two-step plasma doping process. The first step plasma process uses a heavy carrier gas, such as a carrier gas with an atomic weight equal to or greater than about 20 amu, to make the surfaces of fin structures amorphous and to reduce the dependence of doping rate on crystalline orientation. The second step plasma process uses a lighter carrier gas, which is lighter than the carrier gas for the first step plasma process, to drive the dopants deeper into the fin structures. The two-step plasma doping process produces uniform dopant profile beneath the outer surfaces of the fin structures.

Claims20

Dependent claims

A method of doping shallow lightly doped source and drain (LDD) regions of fin structures on a substrate, comprising:

applying a first doping plasma on the shallow LDD regions of the fin structures, wherein the fin structures have surfaces with more than one crystalline orientation, wherein a first source gas of the first doping plasma includes a first dopant-containing gas and a first carrier gas, wherein the first dopant-containing gas includes the dopant, wherein the doping rate of the first doping plasma is significantly the same on different surfaces of the fin structures with more than one crystalline orientation;
and
applying a second doping plasma on the shallow LDD regions of the fin structures after the first doping plasma is applied;
wherein a second source gas of the second doping plasma includes a second dopant-containing gas and a second carrier gas, wherein the second doping plasma delivers the dopant deeper below surfaces of the shallow LDD regions of the fin structures.

1 more element

Dependencies are inferred from the claim text.

Mechanisms for forming ultra shallow junction

Life of this patent

Mechanisms for forming ultra shallow junction

Life of this patent

Abstract

Claims20