On the threshold Voltage of symmetrical DG MOS capacitor with intrinsic silicon body

An analytical expression explicitly relating the potential and the electric field at the oxide-semiconductor interface of a symmetrical double-gate oxide-intrinsic semiconductor-oxide system is derived. The expression is continuously applicable to all regimes of operation. The "turn-on" behavior of the system is studied and an "extrapolated" threshold voltage is uniquely defined. Opposite to the behavior of a conventional bulk metal-oxide-semiconductor capacitor realized on a doped substrate, this threshold voltage is shown to decrease with increasing oxide thickness.