"Silicon has been the common choice as semiconductor material since the 1960s, and it still constitutes more than 90 percent of the electronic device types available in the market. The most pressing and visible problem with silicon is its thermal conductivity. The use of cooling systems is inefficient and serve as a major source of waste. Electronic applications require an alternative to silicon that enables devices to be smaller, cooler, faster, powerful, and cleaner. Diamond is the ideal alternative material; it can perform at higher temperatures than silicon without degrading, it can be efficiently cooled, and it tolerates high voltages before breaking down. Therefore, the growth of high-quality single crystal diamond is imperative for further advancing optical and electronic applications of diamond. Industrial applications require large and defect-free SCDs grown at high growth rates and at low cost. The primary objective of this investigation is to address the big challenges facing the diamond growth: (1) the rapid growth, (2) the growth of high quality, and (3) the large volume growth of single crystal diamond (SCD). In this thesis research activity, the growth of SCD is performed in a MSU-design microwave plasma cavity reactor at a constant pressure of 240 Torr and high discharge power densities that are > 500W/cm3 . SCD substrates were successfully grown using specially selected and optimized pocket holder designs. These pocket holder designs create an appropriate thermal environment to shield the diamond substrate from the intense microwave discharge. A growth recipe using these pocket holders was developed. This growth recipe controls the substrate temperature (Ts) and the incident microwave power (Pinc) in a prescribed function of growth time. This growth recipe allows for a polycrystalline diamond (PCD) rimless, uniform single SCD growth process. In one continuous process run PCD rimless and increased diamond surfaces areas of over 2 times were achieved. Specifically, an extensive exploration of the pocket holder diamond growth process was experimentally performed using 3.5 mm x 3.5 mm diamond seeds. During these experiments, the substrate temperature Ts was held constant at 1020°C ± 5°C while the growth time, input power, and pocket depth were varied. Thick (up to 1.9 mm) and enlarged surfaces (up to 2 times) were grown in one continuous process run. After laser cutting and polishing high quality diamond plates with low-stress and low defect densities were obtained. By varying the pocket aperture, enlarged PCD rimless surfaces (up to 2.3 times) were grown in one process run. It was found that, there is a range of optimal pocket depths and apertures that can grow SCD both vertically and horizontally. One more diamond growth step was added to the smooth and large diamond top surfaces of the first growth step. In these extra growth experiments, the resulting grown SCD substrates had a top surface area that was enlarged up to 2.7 times. Finally, the lateral SCD growth versus time was photographically evaluated while the growing diamond substrate still was completely in the pocket. Results show the lateral growth of SCD as a function of time and also show the PCD growth on the substrate holder as a function of the time. This photographic technique is very useful in investigating in-situ CVD diamond growth as a function of time and can be employed in many other CVD diamond growth experiments."--Pages ii-iii.
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