In this work we mainly report on the analysis of polycrystalline 3C–SiC films grown by electron cyclotron resonance-chemical vapor deposition (ECR-CVD) on 4in. (100) and (111) c-Si wafers, using a H 2 +SiH 4 +CH 4 gas mixture at substrate temperatures in the range 930–1050°C. Structural properties of the films were analyzed by X-ray diffractometry, micro-Raman spectroscopy and transmission electron microscopy, while the elemental composition was determined by Rutherford backscattering (RBS) technique. Micro-Raman measurements performed on the SiC layers show a peak around 796cm −1 due to transversal optical phonons of the crystalline SiC matrix, while neither carbon clusterization in graphitic phase nor Si clusterization in amorphous phase was observed. TEM analyses show a polycrystalline columnar structure with lateral crystal dimensions ranging from 300 up to 1400Å. The crystals orientation is very close to that of (100) and (111) Si substrates, as revealed by X-ray and electron diffraction.