A self-aligned enhancement-mode AlGaAs/InP MISFET

An enhancement-mode insulated-gate field-effect transistor (FET) has been fabricated by a self-aligned technique on semi-insulating InP substrate with an AlGaAs gate barrier grown by molecular beam epitaxy (MBE). A device with a gate length of 1 µm exhibited a transconductance of 134 mS/mm and a threshold voltage of 0.9 V. The characteristics are insensitive to light down to 77 K and hysteresis is completely absent. The performance of this device shows that the fabrication of enhancement-mode devices on severely lattice-mismatched heterostructures is feasible.