Double-gate SOI MOSFET is proposed to overcome the scaling limit of bulk MOSFETs. The device structure and corresponding device characteristics are quite different from those of bulk MOSFETs. The potential distribution of the device is investigated. The models for long channel and short channel devices are derived. The results show that remarkable attention should be paid to the threshold voltage adjustment of the double-gate SOI MOSFETs. n+-p+ polycrystalline Si gate double-gate SOI MOSFETs are also proposed to adjust the threshold voltage without introducing new gate materials, and their superb device characteristics are demonstrated.
Keywords: Characteristic length, Double-gate, Fully-depleted, Gate length, Poisson equation, Scaling theory, Short channel effects, Short channel immunity, SOI, Subthreshold swing, Surface potential, Threshold voltage.