Well and punch through stopper formation using conformal doping

Abstract

A method for doping fins includes depositing a first dopant layer at a base of fins formed in a substrate, depositing a dielectric layer on the first dopant layer and etching the dielectric layer and the first dopant layer in a first region to expose the substrate and the fins. A second dopant layer is conformally deposited over the fins and the substrate in the first region. The second dopant layer is recessed to a height on the fins in the first region. An anneal is performed to drive dopants into the fins from the first dopant layer in a second region and from the second dopant layer in the first region to concurrently form punch through stoppers in the fins and wells in the substrate.

Description

BACKGROUND[0001]Technical Field[0002]The present invention relates to semiconductor processing, and more particularly to fin field effect transistor (finFET) devices and methods for formation that include doping of punch through stoppers and wells using conformal doping.[0003]Description of the Related Art[0004]Solid phase doping processes for doping fins is very complex. Typical processing for complementary metal oxide semiconductor (CMOS) fins involves deposition and patterning of a double layer nitride on n-type field effect transistors (NFETs) and a single layer nitride formed on p-type field effect transistors (PFETs). Different layers are processed at the bottom of fins for etching shallow trench isolation regions (STI) adjacent to PFET fins, etc. The processing involves a number of processes that switch back and forth between NFET and PFET regions—blocking one region to process the other. Such processing adds complexity and cost to the fin doping process.SUMMARY[0005]A method...

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