In this work, diamond thin films were deposited using hot filament chemical vapour deposition (HFCVD) technique on Si substrate. Diamond films are typically classified into nano-crystalline diamond (NCD; grain size <100 nm) and micro-crystalline diamond (MCD; grain size >500 nm) based on their grain size. Process parameters such as the ratio of methane and hydrogen concentration (% CH4/H2) and chamber pressure were varied to grow MCD and NCD films. NCD and MCD films will be used as substrate to improve the performance of MEMS resonator. Structural characteristics and quality of the MCD and NCD films were confirmed using Raman spectroscopy and the surface features were imaged using high resolution scanning electron microscopy (HRSEM). © Springer Nature Switzerland AG 2019.