Parameter Extraction and Power/Performance Analysis of Monolithic 3-D Inverter (M3INV)

An equivalent circuit model of monolithic 3-D inverter (M3INV) considering the electrical coupling between the stacked metal-oxide-semiconductor field-effect transistors (MOSFETs) is proposed. We conduct the parameter extraction with technology computer-aided design (TCAD) simulations, where LETI-UTSOI model in HSPICE is used for the bottom PFET and the top NFETs. Their parameters are extracted by fitting their current-voltage (for dc analysis) and capacitance-voltage (for transient ac analysis) characteristics. The parameters extracted from the LETI-UTSOI model contain the electrical coupling at the gate of the bottom MOSFET. In order to extract external capacitances such as monolithic intertier via (MIV)-to-MIV and MIV-to-contact in M3INV, we use two structures, the first that contains MIVs and metal lines and the second that does not. We observe that the dc and transient characteristics of M3INVs built using our extracted parameters match the TCAD mixed-mode circuit simulation results considerably well. Finally, we build and analyze ring oscillators using our M3INV to demonstrate the coupling impact on power and performance.