Influence of the Chemical Properties of the Substrate on Silicon Quantum Dot Nucleation

We have studied the influence of SiO 2 surface properties on the nucleation and growth of silicon quantum dots (Si-QDs) deposited by SiH 4 low-pressure chemical vapor deposition (LPCVD). First, the effect of siloxane groups (Si-O-Si) strain at the SiO 2 surface layer, characterized by Fourier transform infrared (FTIR) spectroscopy, is studied. We evidenced an increase of Si-QD nucleation with the strain of siloxane groups in the SiO 2 substrate layer. Second, the Si-QD nucleation strongly depends on the surface silanol group (Si-OH) density. This density, controlled by chemical and thermal treatments, is measured by multiple internal reflexion (MIR) FTIR. Very high Si-QD densities larger than 10 12 / cm 2 are obtained on highly hydroxylated SiO 2 .