Atomic-layer doping in Si by alternately supplied NH3 and SiH4

Abstract

Low-temperature Si growth on the atomic-layer order nitrided Si(100) surface with N amount of 1–6×1014 cm−2 formed by NH3 reaction at 400 °C were investigated using an ultraclean low-pressure chemical vapor deposition system. The epitaxial growth of Si film on the nitrided Si(100) with the initial N amount as high as about 3×1014 cm−2 is realized at 500 °C, although the film becomes amorphous in the case at the initial surface N amount of 6×1014 cm−2. By the analysis of the x-ray photoelectron spectroscopy, it is observed that the surface structure of the atomic-layer order nitrided Si(100) is changed into Si3N4 structure by the increase of the surface N amount. It is suggested that the crystallinity of Si film deposited on the atomic-layer order nitrided Si(100) is degraded by the existence of Si3N4 structure. Depth profile of N atomic-layer doped Si film clearly shows that most of the N atoms are confined within about 1-nm-thick region.