Reducing or eliminating pre-amorphization in transistor manufacture

摘要

A method for fabricating field effect transistors using carbon doped silicon layers to substantially reduce the diffusion of a doped screen layer formed below a substantially undoped channel layer includes forming an in-situ epitaxial carbon doped silicon substrate that is doped to form the screen layer in the carbon doped silicon substrate and forming the substantially undoped silicon layer above the carbon doped silicon substrate. The method may include implanting carbon below the screen layer and forming a thin layer of in-situ epitaxial carbon doped silicon above the screen layer. The screen layer may be formed either in a silicon substrate layer or the carbon doped silicon substrate.

主权项

1. A method for forming an NMOS field effect transistor (FET) in a doped well of a substrate, the NMOS FET having a source and a drain, comprising:
forming an epitaxial carbon-containing silicon layer in the doped well; implanting dopants to form an NMOS anti-punchthrough layer positioned below the carbon-containing silicon layer; implanting dopants in the epitaxial carbon-containing silicon layer to form an NMOS screen layer, the NMOS screen layer being positioned laterally between eventual positions of the source and the drain; annealing the substrate; following implanting of all dopants, depositing a substantially undoped epitaxial layer on the epitaxial carbon-containing silicon layer; and forming a plurality of isolation structures to define transistor regions.