Influence of gas flow ratio on formation of silicon nanocrystals in SiNx:H

Si-rich Silicon nitride SiNx: H films were grown on silicon substrates with LF-PECVD technique with a gas mixture of SiH4 and NH3 at flow ratios R from   0.25 up to 6.  Thermal annealing at 1100 °C for 1 hour in the... [ view full abstract ]

• Si-rich Silicon nitride SiNx: H films were grown on silicon substrates with LF-PECVD technique with a gas mixture of SiH₄ and NH₃ at flow ratios R from   0.25 up to 6.  Thermal annealing at 1100 °C for 1 hour in the nitrogen ambient was applied to form the Si nanocrystals in the films that have been investigated by x-Ray diffraction, scanning electron microscopy and Raman scattering spectrum. Our experimental results reveal that the silicon nanoclusters can be precipitated from the hydrogenated silicon rich nitride films produced with lower ratio (R<2). It appears that the variation of NCs-Si size and crystalline fraction F_c were intensively depended on the excess silicon content. A high crystalline volume fraction of 81% is obtained for a film deposited at R=0.25, and a dominance of silicon nanocrystallite having the sizes within the range 8–10 nm.