Carbon vacancy control in p+-n silicon carbide diodes for high voltage bipolar applications

Abstract

Controlling the carbon vacancy (VC) in silicon carbide (SiC) is one of the major remaining bottleneck in manufacturing of high voltage SiC bipolar devices, because VC provokes recombination levels in the bandgap, offensively reducing the charge carrier lifetime. In literature, prominent VC evolutions have been measured by capacitance spectroscopy employing Schottky diodes, however the trade-offs occurring in the p+-n diodes received much less attention. In the present work, applying similar methodology, we showed that VC is re-generated to its unacceptably high equilibrium level at ∼2 VC cm−3 by 1800 °C anneals required for the implanted acceptor activation in the p+-n components. Nevertheless, we have also demonstrated that the VC eliminating by thermodynamic equilibrium anneals at 1500 °C employing carbon-cap can be readily integrated into the p+-n components fabrication resulting in VC cm−3, potentially paving the way towards the realization of the high voltage SiC bipolar devices.