Beyond CMOS: Logic suitability of In_0.7Ga_0.3As HEMT

We have fabricated 100 nm InAlAs/InGaAs HEMTs that feature a tunneling cap designed to minimize parasitic resistance. We have characterized these devices from the point of logic, studying figures of merit such as gate delay (CV/I), subthreshold slope (S), drain-induced barrier lowering (DIBL), and ION/IOFF. We have found that these devices exhibit promising logic characteristics. In particular, 100 nm Lg devices yield DIBL as low as 80 mV/V, S of 77 mV/decade, and ION/IOFF ratio in excess of 103 with a gate delay of about 1.2 ps. We have also found that these devices, from a logic application point of view, at 100 nm gate length have reached their scaling limit. Realizing the logic potential of In0.7Ga0.3As HEMTs will require a more scalable device design with better electrostatic integrity. If this can be accomplished, InGaAs HEMTs could well be the technology of choice when the CMOS roadmap comes to end.