High-Performance Si/SiGe n-Type Modulation-Doped Transistors

Enhancement-mode Si/SiGe n-type modulationdoped transistors with a 0.5-μm-length T-gate have been fabricted. Peak transconductances of 390 mS/mm at room temperature and 520 mS/mm at 77 K have been achieved. These high values are attributable to a combination of the high quality of the material used, having a room temperature mobility of 2600 cm²/V •s at an electron sheet concentration of 1.5 × 10¹² cm², and an optimized layer design that minimizes the parasitic series resistance and the gate-to-channel distance. © 1993 IEEE