High-Speed Steep-Slope GaInAs Impact Ionization MOSFETs (I-MOS) With SS = 1.25 mV/dec—Part I: Material and Device Characterization, DC Performance, and Simulation

Digital electronics power consumption evolved into a major concern: at the current pace, general-purpose computing energy consumption will exceed global energy production before 2045. The principal approach to curbing energy consumption in digital applications calls for “steep-slope” devices with an inverse subthreshold slope (SS) parameter well below the “ln(10) $\cdot $ kT / ${q}$ ” limit of conventional electronics (60 mV/dec at 300 K). Impact ionization MOSFETs (I-MOS) provide an avenue for steep-slope device realization. High-mobility narrow gap III - V semiconductor channel materials have not yet been investigated for I-MOS applications. We hereby report E-mode narrow bandgap GaInAs-based I-MOS devices with an SS of 1.25 mV/dec maintained over five orders of magnitude in drain current and ${I}_{ \mathrm{\scriptscriptstyle ON}}/{I}_{ \mathrm{\scriptscriptstyle OFF}}$ ratios >10⁶ at 300 K (>10⁹ at 15 K) for a gate length of ${L}_{\text {G}} \,\,=100$ nm. Part I of this work focuses on the materials and device fabrication and analysis, device dc characterization, and modeling. The present GaInAs devices are the first I-MOS transistors to display a robust steep-slope effect at low voltages ${V}_{\text {DS}} < 1.9$ V at 300 K and < 1 V at 15 K. Part II describes the dynamic switching (including clarifications on the role of hysteresis) and RF characteristics of GaInAs I-MOS devices and benchmarks them with respect to other steep-slope technologies.