Wide band gap silicon carbon nitride films deposited by electron cyclotron resonance plasma chemical vapor deposition

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We report on the growth of continuous polycrystalline silicon carbon nitride (SiCN) films using electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR CVD). High nucleation density up to 1011 cm−2 was demonstrated, which is much higher than other CVD methods. The resultant SiCN films were thus much smoother and continuous, allowing measurement of various properties of the film. RBS studies show that Si, C, and N are present in the film and that the nitrogen content in the film could reach as high as 57%. The average grain size estimated from HRTEM images was about 20nm. For the SiCN film with 4.8at.% carbon content, all d-spacings of the film observed from TED pattern were similar to those of α-Si3N4. High resolution XPS scans showed that the presence of Si–C bonds within the film was negligible. From the RBS, XPS and the TEM results, we suggest the silicon carbon nitride film possessed the same structure as α-Si3N4 with around 4.8at.% C substituting for Si. It is also demonstrated that this new compound has a direct band gap of about 4.4eV and an impurity band gap at around 3.0eV. Thus the ternary SiCN compound reported here constitutes an important addition to the wide band gap material with gap energies within the blue spectral region. Furthermore, the nanocrystalline SiCN films deposited by the ECR CVD process were excellent for buffer layers of SiCN film growth. This provides the possibility of growing continuous and even textured SiCN films at a reasonable growth rate, which enables various studies of the films.