Strained-quantum-well, modulation-doped, field-effect transistor

A new modulation-doped field-effect transistor structure which employs a thin (8 nm) strained layer of In 0.25 Ga 0.75 As as the channel is described. The prototype device with a 2.9 ¿m gate length had a peak, room-temperature, unilluminated extrinsic transconductance of 91 mS/mm (VDS = 1 V). If device performance scaled linearly with gate length to 1 ¿m, as do (Al, Ga)As/GaAs, single-interface, modulation-doped FETs, this is the best room-temperature performance reported to date for an (In, Ga)As channel, modulation-doped transistor. Furthermore, the transconductance of the strained-quantum-well transistor proved to be almost constant with gate voltage, varying less than 13% over a 0.5 V range at 77 K. This will allow the fabrication of extremely linear microwave amplifiers and supports the assertion that the current conduction path is the (In, Ga)As channel.