Thermal Stress and Intrinsic Stress in Nanocrystalline Diamond Film Prepared by Hot Filament Chemical Vapor Deposition

摘要

Thermal and intrinsic stresses in nanocrysatlline diamond film (NCD) prepared by double bias-assisted hot filament chemical vapor deposition (HFCVD) are investigated in this paper. The finite element analysis (FEA) model is set up to simulate the thermal stress in NCD. The discontinuous sharp of the film results in the stress concentration at the film's edge. The intrinsic stress is measured by X-ray diffraction "sin~2ψ" method. The low elastic modulus of NCD leads to the low thermal stress in NCD. The decrease of ambient pressure results in the decrease of grain size of diamond and the increase of grain boundaries. The compression intrinsic stress is correlative with the microstructure detects and non-diamond impurities in diamond film. The intrinsic stress in nanocrystalline diamond film increases with the decrease of grain size. The smaller grain size and greater non-diamond carbon content result in a larger intrinsic stress.