A dynamic source-drain extension (DSDE) MOSFET using a separately biased conductive spacer

We present a novel device to control short channel effects: a conductive spacer. Placed adjacent to (but isolated from) the gate stack, the conductive spacer functions as an auxiliary gate and is biased independently from the principal gate. This novel auxiliary gate is able to invert a portion of the channel adjacent to the LDD on both the source and the drain side, decreasing the effective channel length. Consequently, it is easier to turn the gate "off" and "on". Using T-CAD simulations, we show a four orders of magnitude reduction in I_OFF (at an I_DSAT of 700 μA/μm) using the conductive spacer device. Conductive spacers may be useful as scaling continues. It is predicted that nano-scale pass gates with I_OFF values as low as 1 pA/μm may be attainable