Low Thermal Budget (<250 °C) Dual-Gate Amorphous Indium Tungsten Oxide (IWO) Thin-Film Transistor for Monolithic 3-D Integration

We experimentally demonstrate back-end-of-the-line (BEOL) compatible (<;250 °C thermal budget)1% tungsten (W)-doped amorphous In ₂ O ₃ (IWO) back-gate field-effect transistor (BGFET) and dual-gate field-effect transistor (DGFET) with 7-nm channel thickness. The 100-nm channel length IWO DGFET exhibits excellent subthreshold slope of 73 mV/decade, record I _D,SAT of 370 μA/μm, and on-off ratio > 4 × 10 ⁹ at V _DS = 1 V and V _GS -V _TH = 2 V. We identify fundamental transport mechanisms that limit electron mobility in amorphous IWO transistors at different gate-bias (V _GS ) and temperature. Benchmarking reveals that amorphous IWO FETs are promising candidate for in situ transistor fabrication in the BEOL for enabling high-performance monolithic 3-D (M3-D) integrated circuits.