— A new operation mode using a partially depleted hybrid lateral BJT-CMOS inverter on SOI, named as a new unified-BiCMOS (U-BiCMOS) inverter, is proposed. The scheme utilizes the gated lateral npn or pnp BJT inherent of nor p-channel MOSFETs. Forward current is applied to the base terminal of the channel MOSFETs, with a normal pull-up or pull-down MOSFET as a current source, where each drain terminal is connected to the corresponding base terminal of the inverter. A logic scheme is also proposed to control the gates of the pull-up or pull-down MOSFETs in switching states using output signals made from two CMOS inverters with different resistance ratios. Circuit simulation using 0.35 µm BSIM3v3 model parameters for MOSFETs and a current gain of βF =100 for BJTs, the speed of a domino CMOS full adder with the U