A Study on Fabrication and Heat Dissipation of Polycrystalline Diamonds

In this paper, we have theoretically investigated the effect of grain size on the thermal conductivity of diamond by molecular dynamics (MD) calculations, and experimentally prepared different grain sizes of diamond. Through the calculation results, it can be known that the thermal conductivity of diamond increases with the size of the grains. Then, we have prepared polycrystalline diamond (PCD) films by MPCVD equipment and investigated the effect of growth temperature on the grain size of PCD films. Combining the scanning electron microscopy (SEM) results with the growth conditions, we find that the grain size of PCD films is positively correlated with the growth temperature. Subsequently, the PCD films have been tested by Raman spectroscopy and XRD pattern, the results show that all the samples are PCD films and the grain size results obtained by XRD full width at half maxima analysis are in agreement with the SEM results. The research results of this paper may be helpful to promote the application of PCD films in high-frequency and high-power electronic devices.