HIGH-PERFORMANCE SI SIGE N-TYPE MODULATION-DOPED TRANSISTORS/

Enhancement-mode Si/SiGe n-type modulation-doped transistors with a 0. 5-mum-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. T hese 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 x 10(12) cm2, and an o ptimized layer design that minimizes the parasitic series resistance a nd the gate-to-channel distance.