GaSb metal-insulator-semiconductor field-effect-transistors

The metal-insulator-semiconductor FET (MISFET) principle was demonstrated for the first time in a new material, GaSb. P-channel insulated-gate gallium antimonide field-effect transistors (GaSb MISFETS) were fabricated and characterized in a wide range of operating temperatures. Such devices are important as basic building blocks for self-scanned 1.8µm imagers for night vision applications. The GaSb MISFETS are planar, closed-geometry devices. The GaSb substrates are oriented and Te-doped to ND ≈ 2×10¹⁷cm^-3. The source and drain were formed by either Be-implantation or Zn-diffusion. Aluminum is used for both gate electrode and source and drain contacts. Low temperature pyrolytic silicon dioxide was used as gate insulator. The GaSb MISFETS are enhancement devices which follow the ideal MOSFET current-voltage characteristics (i.e., ID α (VG-VTH)²). The threshold voltages vary linearly from ∼ 0 volts to -14 volts as temperature decreases from 300K to 12K. Surface hole mobility of 188 cm²/V-sec was obtained at 300K.