Composition and microstructure of beryllium carbide films prepared by thermal MOCVD

• Non-columnar-crystal Be2C films were firstly prepared by thermal MOCVD.
• Beryllium carbide was always the dominant phase in the films.
• α-Be and carbon existed in films deposited below and beyond 400 °C, respectively.
• Morphology evolved with temperatures and no columnar grains were characterized.
• The preferred substrate temperature for depositing high quality Be2C films was 400 °C.

Beryllium carbide films without columnar-crystal microstructures were prepared on the Si (1 0 0) substrate by thermal metal organic chemical vapor deposition using diethylberyllium as precursor. The influence of the substrate temperature on composition and microstructure of beryllium carbide films was systematically studied. Crystalline beryllium carbide is always the dominant phase according to XRD analysis. Meanwhile, a small amount of α-Be phase exists in films when the substrate temperature is below 400 °C, and hydrocarbon or amorphous carbon exists when the temperature is beyond 400 °C. Surfaces morphology shows transition from domes to cylinders, to humps, and to tetraquetrous crystalline needles with the increase of substrate temperature. No columnar grains are characterized throughout the thickness as revealed from the cross-section views. The average densities of these films are determined to be 2.04–2.17 g/cm3. The findings indicate the substrate temperature has great influences on the composition and microstructure of the Be2C films grown by thermal MOCVD.