Properties of selectively doped heterostructure transistors incorporating a superlattice donor layer.

We report on transport properties and device performance of an improved structure of selectively doped heterostructure transistor (SDHT) incorporating a short-period (30Angstroms) Al(0.6)Ga(0.4)As/n-GaAs superlattice donor layer. We show that this superlattice - SDHT (S(2)DHT) is a good candidate for both low-temperature packaged operation and room-temperature applications. At low temperature in the dark the device exhibits no drain 1-V distortion and very little shift in the threshold voltage. At room temperature the device loosens the uniformity requirement of recess-gate etching in processing and has a larger operating range of high transconductance (~250 mS/mm) than conventional SDHTs.