Diamond thin films have numerous potential technological applications due to their extraordinary physical properties. Improvements in film quality, deposition rate, and uniformity are keys to the realization of this potential, requiring understanding and control of diamond nucleation and growth. In particular, heteroepitaxial diamond thin films for semiconductor devices have yet to be achieved. A multifaceted approach involving both experimental measurements and theoretical predictions of species impinging upon the growing surface, coupled with characterization and modeling is essential for unlocking the complexities of diamond deposition chemistry. The PIs plan to develop a mechanistic understanding of diamond growth which can be used for the design of equipment and processes for crystalline, high quality diamond thin films. The kinetic mechanisms of diamond growth will be experimentally probed using a hot-filament reactor. Using molecular beam sampling to extract the species striking the heated wafer surface, the precursors for diamond deposition will be measured using Resonancely Enhanced Multiphoton Ionization Mass Spectrometry (REMPI/MS). The gas phase concentrations will also be measured using Laser Induced Fluorescence (LIF) and Coherent, Anti-Stokes Raman Spectroscopy (CARS). Both chemical and physical transport models will be constructed and tested against the experimental data in order to identify the main processes or steps that control the kinetics of diamond nucleation, growth, and defect formation. The defect structures of diamond films will be measured using Carbon 13 solid state Nuclear Magnetic Resonance (NMR) as well as conventional techniques. The NMR results will be analyzed to identify the type and quantity of defects and will be correlated to conventional techniques such as Raman scattering to relate these studies to others in the literature. Selective Carbon 13 isotopic labeling will be used to gain insight into the kinetics of diamond formation. The nucleation of diamond growth will be quantified using Scanning Tunneling Microscopy (STM) to count and measure the nuclei during the initial phases of growth. Devices will be fabricated and tested, and their characteristics will be correlated with the diamond growth parameters and film characterization.
