Using point defect engineering to reduce the effects of energy nonmonochromaticity of B ion beams on shallow junction formation

Abstract

We have shown that energy contamination introduced by deceleration technology, for increasing the beam currents available for low energy boron implants, can affect fabricated junctions adversely. Energy contamination at a level of 0.1% can extend the profile of 0.5 keV B implants 10 nm deeper after a 1050 °C spike annealing. A highly monoenergetic beam with energy contamination less than 0.1% is required for submicron devices. Furthermore, we have used MeV implantation as a technique of point defect engineering (PDE) to control boron diffusion. PDE can reduce boron clustering and enhance boron activation. Diffusion of B in the tail region has been reduced significantly and the boron profile is much sharper. PDE lowers the critical requirement for beam purity. We conclude that shallower and sharper box-like boron junctions can be achieved by PDE with sub-keV B implants with highly monoenergetic beams.