Heavy atomic-layer doping of nitrogen in Si 1 − xGe x film epitaxially grown on Si(100) by ultraclean low-pressure CVD

Abstract

N atomic-layer doping in a nanometer-order Si/Si 1 − x Ge x /Si(100) heterostructure using ultraclean low-pressure chemical vapor deposition and its thermal stability at 650 °C were investigated. In the Si 0.5Ge 0.5 epitaxial layer, it is found that a N doping dose of 6 × 10 14 cm − 2 can be confined within an about 1.5 nm-thick region even after 650 °C heat treatment in contrast to the result for Si cap layer growth on the thermally nitrided Si(100) with a N doping dose of 6 × 10 14 cm − 2 which was found to be amorphous. Moreover, it is suggested that the confined N atoms in Si 1 − x Ge x preferentially form Si–N bonds and that formation of Si 3N 4 is enhanced by the heat treatment at 650 °C.