The effects of surface passivation on the electrostatics of the UTB SOI devices

The surface passivation conditions at top and bottom channel-oxide interface modify channel band structure and band gap of the (Ultra-Thin Body) UTB device. In this work, the channel band structure is calculated using the sp
³
d
⁵
s
^*
tight-binding method with various passivation energies and passivation strategies. The interaction between quantum confinement and the surface passivation effect is investigated. The effect of surface passivation energy on electrostatics parameters, such as threshold voltage and integrated charge density as a function of gate voltage, is shown over a wide range of SOI channel thicknesses. A significant reduction in threshold voltage is seen at lower passivation energies. The thin channel is shown to be more sensitive to the surface passivation energy below threshold voltage as compared to thicker channels, while, the importance of properly passivating both the top and the bottom interface, simultaneously, to reduce the off-state current is also shown.