1. Could someone help me to determine the gate oxide capacitance for a MOSFET?
2. I know the oxide thickness, what more do I need to find it out?
3. What is the equation? C= eps*area/thickness ?
Of course the equation is valid at any scale, but your problem is a little more complicated because the capacitance of a MOS structure is dependent by the conductivity of semiconductor region under oxid, so is dependent by voltage applied to MOS, because this voltage will modulate the conductivity of semiconductor right away under oxide.