Evidence of negative bias temperature instability in 4H-SiC metal oxide semiconductor capacitors

Generation lifetimes and interface state densities of n-type 4H-SiC metal oxide semiconductor (MOS) capacitors are characterized by using the pulsed MOS capacitor technique. A decrease in lifetime and increase in interface state density occurs when the devices are negatively biased at 400°C. This behavior is consistent with an effect seen in Si∕SiO2 devices known as negative bias temperature instability. A portion of the lifetime degradation caused by this effect can be recovered by removing the negative bias as well as by positively biasing the device.