2-kbit Array of 3-D Monolithically-stacked IGZO FETs with Low SS-64mV/dec, Ultra-low-leakage, Competitive μ-57 cm2/V-s Performance and Novel nMOS-Only Circuit Demonstration

We demonstrate 3D monolithically-stacked IGZO FETs with competitive performance for BEOL circuits. The FETs show excellent switching electrostatics with near-deal subthreshold swing, ultra-low leakage density (~10
^-6
A/cm
²
) and superior electron mobility (μ
eff
= 57 cm
²
/V-s). The device fabrication are achieved at low-temperatures (T≤350°C), making the process highly compatible with low-thermal budget Cu interconnect. We have enabled body-contacted IGZO FETs, capable of dynamic body biasing and implemented these devices into functional novel circuits. We show the feasibility of stacking these FETs with little performance impact.