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 micron gate length had a peak, room-temperature, unilluminated extrinsic transconductance of 91 mS/mm. If device performance scaled linearly with gate length to 1 micron, 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 chanel, modulation-doped transistor. Furthermore, the transconductance of the strain-quantum-well transistor proved to be almost constant with gate voltage, varying less than 13 percent 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.