Atomic-scale origins of bias-temperature instabilities in SiC-SiO 2 structures


We find that atomic-scale mechanisms for bias-temperature instabilities (BTIs) in SiC/SiO2 structures can differ significantly from those in Si/SiO2 structures. The measured effective-activation energies for BTI in 4H-SiC metal-oxide-semiconductor capacitors, 0.23±0.02 eV for p -type and 0.12±0.02 eV for n -type, are essentially identical to the respective dopant ionization energies, which are much larger than in Si. This suggests a key role for carrier release from deep dopants for BTI in SiC. In addition, asymmetric degradation is observed under switched-bias stress in p -type and n -type SiC, as a result of the reconfiguration of O vacancies in SiO2 layer after hole capture. © 2011 American Institute of Physics.

Publication Title

Applied Physics Letters