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 a plurality of FETs in a substrate, comprising:
forming at least one PMOS FET; and forming at least one NMOS FET, the forming at least one NMOS FET includes:
implanting a dopant to form an NMOS anti-punchthrough layer;implanting a dopant to form an NMOS screen layer;forming a carbon-containing region above the NMOS screen layer;forming a diffusion-inhibiting region below the NMOS screen layer using a diffusion-inhibiting material implant, wherein the carbon-containing region and the diffusion-inhibiting region are operable to substantially limit diffusion of the NMOS screen layer dopants;annealing using a low thermal budget anneal; anddepositing a substantially undoped epitaxial silicon layer on the carbon-containing region; and forming trench isolation structures to electrically isolate the plurality of FETs from one another.