Back-gated field effect in a double heterostructuremodulation-doped field-effect transistor

An Al_0.3Ga_0.7As/GaAs/Al_0.3Ga_0.7 As double heterojunction field-effect transistor has been fabricated, the novel feature being a pn junction back gate. A device with 2 μm channel length has yielded a change in transconductance by a factor of 2 for a change in back gate voltage of 1 V. The performance of this device shows that this approach could be used in realising novel devices, such as velocity modulation transistors. Also, the change in threshold voltage with back gate bias could be useful in implementing digital circuits