B6100-141-fabrication and characterization of polycrystalline diamond for thermal management
Lim, Teresa Hui Qi
Date of Issue2015
The studies in this dissertation cover on various techniques to uncover morphologies of diamond films by chemical vapour deposition (MPCVD) method. The characterization of diamond films was carried out by analytical techniques such as scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, Photoluminescence and thermal conductivity is later tested by 3ω Technology. Thermal issue has become more and more important in high power electronic devices and also, responsible for the reliabilities of devices. Power density must be increased while the dimension must be reduced. To overcome this, a material of extremely good thermal conductivity must be used. Diamond is found to possess extremely good thermal conductivity compared to copper, especially single-crystal, natural diamonds. One of diamond properties is having a thermal conductivity of diamond (2200 W/mK) which is 4 times higher than copper. The relationship between grain size, Raman peak, FWHM width and seeding time is investigated and found out that the relation is co-related. It can be observed that once the peak of Raman shifted, the grain size and FWHM width are also affected. A larger grain size is preferred for a better heat conductivity. It is concluded that 15 hours of seeding time with S1, 20g of diamond powder/300ml is the best in growing diamonds of better purity. It is also observed that other than factors like seeding time and amount of diamond powder used, external factors like stress could also alter the morphology of diamond samples. It is essential to control the parameter during growth of diamond in order to achieve desired results. Defects like Nitrogen Vacancy, sp2 and Silicon Vacancy are also closely observed in the process as to define and identify the causes and how they are affecting the quality of diamond films. The results of the characterization will be used as a feedback to better optimize parameters to experiment and to improve the quality of diamond films.
Final Year Project (FYP)
Nanyang Technological University