"Single crystalline diamond (SCD) has the potential to be widely used in high tech applications, i.e. optics, electro-optics and electronics. Currently, the limitation on commercialized diamond applications is the availability of large SCD wafers. SCD wafers of at least two inches in size will be necessary for a commercial adaptation of SCD applications. Today, the availability is limited to approximately 8.0 mm × 8.0 mm SCD wafers. Homoepitaxial growth of SCD material usually does not enlarge the top surface area. Thus, it is necessary to develop SCD engineering approaches to enlarge the wafer dimensions to two inches and above, and to develop key technologies that are required for low cost SCD wafer manufacturing. The primary goal of this thesis is to address and solve some of the key challenges, which will enable technological advancement towards two inch SCD wafers and beyond. Three key diamond process, that have the potential to solve SCD wafer manufacturing issues are investigated in this thesis. These are: (i) laser cutting and shaping of SCD, (ii) ion implantation for SCD wafer manufacturing and (iii) increasing SCD growth rates. Laser processing was investigated for the adaptation of SCD wafer processing and separation. It was found that SCD laser processing can be easily achieved using an infrared diamond cutting laser. A three stage procedure for separation of SCD wafers was established. However, the technology proved ineffective for large area SCD wafers due to material losses. A Lift-Off technique using ion implantation weas introduced as alternative wafer separation technique was investigated. The procedure is virtually loss-free and scalable up to several inches in size. Successful Lift-Off was demonstrated using protons, carbon and oxygen ions, and electrochemical etching. Alternative etching techniques were limited to small wafer dimensions due to diffusion limitations and partial etching of the SCD wafers. Increasing the SCD growth rate and crystalline quality was achieved by increasing the operational pressure regime for microwave plasma assisted chemical vapor deposition from 280 Torr up to 400 Torr. The fundamental reactor behavior was studied by recording the absorbed power densities and the operational field map in this higher pressure regime. Absorbed power densities were increasing from 525 to 670W cm-3 . It was found, that the fixed geometry of the reactor limited the SCD growth, especially above 380 Torr. Thus, a readjustment of the cavity dimensions and substrate position inside the reactor will be necessary to increase the operating pressure even further. SCD growth under high pressures was also explored. Individual deposition runs for different process pressures and methane concentrations were performed. Growth of freestanding high quality SCD plates was demonstrated for process pressures up to 400 Torr. The SCD growth rate increased from 9 to 28 æm h-1 as the process pressure increased from 180 to 380 Torr. The SCD top surface area increased by 40 %. A stable pulsable microwave power supply was used to investigate the formation of pulsed microwave discharges. Video recording of the pulsed discharge formation was performed and the images were analyzed. Six different discharge ignition cases were identified within the parameter space (pulsing durations Ton and Toff, and pulsing power levels Pon and Poff). Finally, preliminary results showed that optimizing the reactor geometry and the use of pulsed excitation has the potential to enhance SCD growth rates while retaining the high crystalline quality. In particular, the experiments indicate, that the growth rate can be increased by 70 to 100 %."--Pages ii-iii.
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