In this study, we investigated the growth mechanism of silicon quantum dots (Si QDs) embedded in a Si-nitride film formed by using plasma-enhanced chemical vapor deposition. Special attention was paid to the influence of the nitrogen source, especially in molecular nitrogen (N2) and ammonia (NH3). We found that the nitrogen source played a decisive role in determining the location of nucleation sites of Si QDs. In the case of the SiH4+NH3 gas source, the Si QDs mainly nucleated at the surface of the Si substrate, in contrast to the case of SiH4+N2 which should no such tendency. We believe that a specific surface reaction of the initially adsorbed NH3 molecules forming lowdimensional structures (NH2-Si-Si-H) on the Si substrate provide the nucleation sites for Si QDs when using a SiH4+NH3 plasma.
ASJC Scopus subject areas
- Physics and Astronomy(all)