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Molecules that bear carbon-fluorine bonds, especially on chiral centres, are becoming of interest to the pharmaceutical industry due to the effects on the bioactivity of a drug molecule. This thesis adds to the pool of chiral α-fluorocarbonyl systems and the discussion of the grey area surrounding their conformational preference. First, dimethyl 2-fluoromalonate was investigated as a nucleophile and as an electrophile. The fluorodiester was successfully reacted with a short series of electrophilic alkylating agents and, separately, a nucleophilic amine. Consequently, in collaboration with GlaxoSmithKline, these two strategies were combined to use dimethyl 2-fluoromalonate as a fluorinated ‘building block’ in the synthesis of a 6-membered fluorolactam. This fluorolactam subsequently underwent an enzymatic chiral resolution to yield an enantiomerically enriched analogue as an intermediate in the synthesis of a pre-clinical candidate spleen tyrosine kinase (Syk) inhibitor being developed by GSK. The process was optimised and quantitatively analysed by a ‘green metrics’ package developed by the EU IMI Chem21 consortium and found to be significantly less wasteful than the literature alternative synthetic route. Work on analogous 5- and 7-membered fluorolactams was carried out following the success of the 6-membered system. In collaboration with Almac Group, another α-fluorodicarbonyl species, ethyl 2-fluoroacetoacetate, was chosen as a substrate for carbonyl reductase (CRED) screening. Enzymatic routes to all four possible diastereomeric fluoroalcohol derivatives were found and work to determine the absolute stereochemistries of the products is ongoing. Following analysis of the structural preferences of the X-ray crystal structures of products developed in this thesis, the final chapter investigates the conformational preference of α-fluorocarbonyl moieties in the Cambridge Structural Database. This research was coupled with NMR experiments and computational calculations, from the literature and our own work, of these species in the solution state to determine that there is a greater syn F-C-C=O preference in more polar environments and that any inherent preference may potentially be overridden by a number of competing factors. The assumption that anti is the preferred conformation of α-fluorocarbonyl species must, therefore, be treated with caution.

Despite the excellent electrical and thermal properties of 4H-silicon carbide (SiC), the fabrication of high-voltage SiC power devices is still proving problematic, being hindered by material defects resulting in low carrier lifetimes and forward voltage drift, and suboptimum ohmic contacts to p-type material. The PiN diode is one such device that suffers from the aforementioned problems, though at the same time is sought after for high voltage power electronics applications due to the prospect of greatly reduced power losses and increased power handling capability than the Si devices currently in use. As such, this thesis is focussed on the development of these devices, investigating various device structures to achieve high reverse blocking voltages as well as developing novel fabrication processes to improve the electrical performance of the devices. Electrical characterisation of ohmic contacts to p-type 4H-SiC showed that Ti/Al-based metal schemes offered the lowest specific contact resistivity of approximately 2.2 x 10-6 Ω-cm2, which was achieved after annealing at 1000°C for 2 minutes. Physical analysis showed that these annealing conditions were optimum for formation of the Ti3SiC2 alloy at the metal-semiconductor interface, the presence of which was found to correlate with lower specific contact resistivity values. Electrical characterisation of first generation PiN diodes designed for blocking 3.3 kV showed that the fabricated devices had a differential on-resistance (Ron,dif f) of 17 Ωm -cm2 at 100 A/cm2 and 25°C, and near-ideal (η = 1.3) characteristics in the diffusion current regime. Based on the measured reverse saturation currents, the carrier lifetime of the fabricated devices was estimated to be 480 ns. Reverse leakage currents were found to vary significantly across the devices, from 5 nA/cm2 up to 200 μA/cm2 at 100 V reverse bias and 25°C. Second generation 3.3 kV PiN diodes, which featured a B-implanted JTE structure, were found to block a maximum reverse voltage of 2.8 kV, which was around 85% of the target value. PiN diodes fabricated with a drift region designed for blocking 10 kV underwent thermal oxidation processes at temperatures ranging from 1400°C to 1600°C in order to increase the carrier lifetime. Devices having undergone no lifetime enhancement treatment were found to have a Ron,dif f of 11.6 mΩ-cm2 at 100 A/cm2 and 25°C, and an ideality factor η = 1.5 in the diffusion current regime. PiN diodes that had undergone thermal oxidation were found to have improved forward characteristics, with devices oxidised at 1500°C exhibiting a Ron,dif f of around 9 mΩ-cm2 at 100 A/cm2 and 25°C, an improvement of nearly 25%. A novel combined thermal oxidation and annealing process was developed and applied to second generation 10 kV PiN diodes; a mean Ron,dif f of 4.45 mΩ-cm2 was achieved, and a carrier lifetime of 1.21 μs was extracted from reverse recovery characteristics; these were both significant improvements on both the second generation control sample and the first generation thermally oxidised PiN diodes.