Characterization of ion-bombarded 4H and 6H silicon carbide

This study investigates the properties of semi-insulating 4H and 6H silicon carbide polytypes. The primary objectives of this study were to measure and evaluate properties created by ion bombardment and determine the potential for such applications as device isolation and current confinement.; The semi-insulating material was created by bombarding the samples with multiple implants of silicon or carbon ions using ion implantation that produced a maximum penetration depth of approximately 2 microns for each ion species. An implant schedule was chosen that produced carrier concentrations in the range of 1019 cm3. Contacts were then added to the samples and resistivity measurements were made after successive annealing of 600°C, 800°C, 1000°C, and 1200°C. The highest resistivity produced over the measured temperature range was 3.6622 x 1011 ohms/cm and was produced from the 4H samples bombarded with silicon and annealed at 600°C. Similarly, the lowest resistivity produced over the measured temperature range was 3.9879 x 105 ohms/cm and was produced from the 6H sample bombarded with carbon and annealed at 1200°C.; Temperature dependent resistivity measurements were also performed to determine the energy activation level of the compensating impurities. The samples measured with the deepest energy level, 0.98eV, were the 6H samples implanted with carbon. A compensation energy level of 0.78eV was measured for both the 4H and 6H samples implanted with silicon whereas a compensation energy level of 0.52eV was measured for 4H implanted with carbon.