Threshold Voltage of Sub-micron In sub 0.53 Ga sub 0.47 As HIGFETs.

We present threshold voltage data for In sub(0.52) AI sub(0. 48) As/In sub (0.53)Ga sub(0.47)As/InP heterostructure insulated gate FETs (HIGFETs) with gate lengths from 1.2micron to 0. 4micron. The refractory-gate, self-aligned fabrication process was applied to MBE-grown structures with 300angstrom In sub (0.53)Ga sub(0.47)As channels and semi-insulating superlattice buffers, to achieve sharp pinchoff with excellent threshold uniformity. HIGFETs with L sub(g) = 1.2micron showed a threshold voltage of -0.076 +- 0.019 volt, making them well-suited to application in Direct-Coupled FET Logic (DCFL) circuits.