High critical field strength and saturation electron velocity of gallium nitride (GaN) makes it a promising material for future compact, high voltage, and high-speed photoconductive switches. Photoconductive semiconductor switches (PCSSs) have advantages for pulsed power applications since it is a device that turns on when illuminated with fast rise time, low jitter, and allows for high repetition rate. Semi-insulating GaN is necessary to sustain the high blocking voltages required for such devices. This is accomplished by compensation doping with doped with iron, carbon, or magnesium. However, a strong photoresponse is also necessary to enable optical triggering of the switch. We have found that carbon-doped GaN (GaN:C) simultaneously reduces the off-state leakage current and extends the blocking voltage, while still allowing for high on-state photocurrent compared to unintentionally doped GaN. However, forming a low resistance contact to highly insulating GaN:C is challenging. Our approach is to study both Si ion implantation and Si-doped confined epitaxial growth as techniques to achieve low resistance N+ contacts. Implantation and activation is a planar process that is promising for formation of contact regions while mitigating high electric field points within the device. In this work, we implant Si with a box profile to a depth of 0.4 μm into GaN:C with carbon concentrations of 5x10¹⁷ and 1x10¹⁸ cm^-3 grown on SiC substrates. Then, a sputtered AlN capping layer is introduced before annealing at various temperatures to preserve the surface from decomposition during annealing. Activation anneals are performed using rapid thermal annealing as well as the previously reported multicycle rapid thermal annealing processes. The AlN capping layer is then selectively wet etched and Ti/Al/Ni/Au contacts are deposited and alloyed at 850 °C. As a comparison, Si-doped low temperature and high temperature GaN layers were grown by MOCVD using a LPCVD SiO₂ mask. Top-to-top lateral PCSSs are fabricated and characterized to identify the impact of the contact processing on the ON-resistance, off-state leakage, blocking voltage, and photocurrent. Finally, as the device is a top-side illuminated lateral device, the electric fields at the surface must be properly managed to realize reliable high voltage operation. The appropriate surface passivation and encapsulation processes to realize field plate structures while simultaneously enabling top-side UV illumination will be discussed.