N-Channel Germanium MOSFET Fabricated Below 360 $^{ \circ}\hbox {C}$ by Cobalt-Induced Dopant Activation for Monolithic Three-Dimensional-ICs

Below 360°C, we demonstrate germanium (Ge) n+/p junction diode and n-channel Ge metal-oxide-semiconductor field-effect transistor (MOSFET) with a low temperature Al/Al₂O₃/GeO₂ gate stack for monolithic 3-D integration using a metal-induced dopant activation (MIDA) technique. In particular, the cobalt (Co) MIDA phenomenon is investigated on Ge damaged by an implantation process. Shallow (~100 nm) source/drain junctions with very low resistivity (5.2 × 10^-4 Ω-cm) are then achieved at very low temperature by the Co MIDA technique. Consequently, high diode and transistor current on/off ratios (~10⁴ and ~10³, respectively) are obtained in this n-channel Ge MOSFET.