A unit cell of a metal oxide semiconductor (MOS) transistor is provided including an integrated circuit substrate and a MOS transistor on the integrated circuit substrate. The MOS transistor has a source region, a drain region and a gate. The gate is between the source region and the drain region. First and second spaced apart buffer regions are provided beneath the source region and the drain region and between respective ones of the source region and integrated circuit substrate and the drain region and the integrated circuit substrate.