  Silicon Carbide (SiC) is a wide bandgap semiconductor material recently being
used in replacement of traditional semiconductors for high-voltage power device
applications. Radiation environments induce defects through displacement damage
in the lattice that can saturate over periods of high energy particle exposure
at various concentrations. Defects are characterized by the formation of
vacancies, interstitials and Frenkel pairs. Using molecular dynamics software
we calculate thermal expansion coefficient (TEC) over and specific heat
capacity at constant volume ($c_v$) values over a temperature range varying
defect concentrations in single crystal 4H-SiC. At a discovered critical defect
density amorphous defect clusters form in the lattice triggering macroscopic
negative thermal expansion across the entire temperature range. Exponential
$c_v$ loss is observed as defect density increases until the isothermal process
becomes completely adiabatic at a identified critical Frenkel pair
concentration. Providing insight to the degradation of SiC from displacement
damage effects can ultimately assist the development of radiation-hardened
electronics.
