Fabrication of silicon quantum dots in SiNx multilayer using hot-wire CVD

A hot-wire chemical vapor deposition (HWCVD) procedure for growing 40 alternating layers of Silicon quantum dots (Si-QD) and SiNx in a single silicon nitride deposition chamber is presented in this paper. Films of 140–160 nm thickness were deposited with a substrate temperature of 250 °C and post-annealed between 800 and 950 °C. Transmission electron microscopy (TEM), secondary ion mass spectroscopy (SIMS) and Raman analysis techniques were used to characterize the samples. The cross-sectional TEM analysis confirms the formation of Si-QD in the range 3–5 nm with a density of 5×1012/cm2 in the Si-QD/SiNx multilayer. The SIMS measurements indicate the variation in Si and N content as the alternating layers of Si and SiNx grow on the c-Si substrate. Deconvolution of the first order Raman spectra shows the presence of a lower frequency peak in the range 517–518 cm−1 corresponding to Si-QD annealed with an increase in the temperature. The intensity ratio at the center frequency of the second order Raman spectrum increases from 0.52 to 0.88 with an increase in the Si-QD size and the annealing temperature.