Breakdown voltage enhancement from channel quantization in InAl/As/n/sup +/-InGaAs HFET's

In/sub 0.52/Al/sub 0.48/As/n/sup +/-In/sub 0.53/Ga/sub 0.47/As HFETs have been fabricated with different channel thicknesses. It is shown that by reducing the channel thickness from 350 to 100 AA, the reverse gate breakdown voltage improves from 9 to 19 V. This is partially attributed to the increased effective bandgap that results from energy quantization in the channel. This bandgap enhancement is directly confirmed by photoluminescence (PL) measurements on the same heterostructures. Channel quantization emerges as a promising approach for exploiting the excellent transport properties of InGaAs with high InAs mole fraction. The principle behind the work should be applicable to other narrow-gap semiconductors.>