High-performance Si/SiGe n-type modulation-doped transistors

Enhancement-mode Si/SiGe n-type modulation-doped transistors with a 0.5- mu m-length T-gate have been fabricated. 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 cm/sup 2//V-s at an electron sheet concentration of 1.5*10/sup 12/ cm/sup 2/, and an optimized layer design that minimizes the parasitic series resistance and the gate-to-channel distance.<
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