The carbon vacancy (VC) is a prominent defect in as-grown 4H-SiC epitaxial layers for high power bipolar devices. VC is electrically active with several deep levels in the bandgap, and it is an efficient “killer” of the minority carrier lifetime in n-type layers, limiting device performance. In this study, we provide new insight into the equilibration kinetics of the thermodynamic processes governing the VC concentration and how these processes can be tailored. A slow cooling rate after heat treatment at ∼2000 °C, typically employed to activate dopants in 4H-SiC, is shown to yield a strong reduction of the VC concentration relative to that for a fast rate. Further, post-growth heat treatment of epitaxial layers has been conducted over a wide temperature range (800–1600 °C) under C-rich surface conditions. It is found that the thermodynamic equilibration of VC at 1500 °C requires a duration less than 1 h resulting in a VC …