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

We report on the growth of continuous polycrystalline silicon carbon nitrid e (SiCN) films using electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR CVD). High nucleation density up to 10(11) cm(-2) was demonstrated, which is much higher than other CVD methods. The resultant S iCN films were thus much smoother and continuous, allowing measurement of v arious properties of the film. RES studies show that Si, C, and N are prese nt in the film and that the nitrogen content in the film could reach as hig h as 57%. The average grain size estimated from HRTEM images was about 20 n m. For the SIGN film with 4.8 at.% carbon content, all d-spacings of the fi lm observed from TED pattern were similar to those of alpha-Si3N4. High res olution XPS scans showed that the presence of Si-C bonds within the film wa s negligible. From the RES, XPS and the TEM results, we suggest the silicon carbon nitride film possessed the same structure as alpha-Si3N4 With aroun d 4.8 at.% C substituting for Si. It is also demonstrated that this new com pound has a direct band gap of about 4.4 eV and an impurity band gap at aro und 3.0 eV. Thus the ternary SiCN compound reported here constitutes an imp ortant 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 growt h. This provides the possibility of growing continuous and even textured Si CN films at a reasonable growth rate, which enables various studies of the films. (C) 1999 Elsevier Science S.A. All rights reserved.