Planar 4H- and 6H-SiC p–n diodes fabricated by selective diffusion of boron

Graphite film was used as a protective and selective mask for realizing diffusion of boron in SiC. Secondary ion mass spectroscopy was employed to identify the diffusion profile in SiC. No significant difference between diffusion profiles in 4H-SiC and 6H-SiC was found. Planar p–n diodes with local p-type emitter regions were fabricated in 4H-SiC and 6H-SiC based on this process. The current density versus voltage (J–V) curves of the formed diodes exhibited good rectification characteristics. The 4H-SiC p–n diodes had much lower forward voltage drops and much less temperature dependence in comparison with 6H-SiC p–n diodes.     

Impact of the electron, proton and helium irradiation on the forward I–V characteristics of high-power P–i–N diode

2.5 kV/100 A high-power P–i–N diode was electron, proton and helium irradiated in a wide range of irradiation doses with irradiation energies in the MeV range. The resulting forward I–V curves were registered in the temperature range 30–125 °C to investigate the magnitude of the crossing point current of the I–V curves––I_XING. I_XING was found to decrease with increasing irradiation dose and to disappear at high doses for all three irradiation treatments with exception of ion irradiated diodes with defect peaks placed deeply into the anode region. Using a simple model based on the thermal and injection dependence of the carrier lifetime, the explanation of this effect is presented with the support of the non-isothermal 2-D device simulation of helium irradiated devices.