Electron transport properties of Si/SiGe heterostructures: Measurements and device implications

We report electron transport properties of modulation-doped Si/SiGe at 300 and 77 K. Record mobilities of 2830 and 18 000 cm2/V s at 300 and 77 K, respectively, have been measured. Depending on the spacer layer thickness, the sheet resistance of the Si channel is in the range of 2000-10 000 Ω/ at 300 K and 450-700 Ω/ at 77 K. The low field electron drift velocity is 2-3 (5-10) times higher than the corresponding velocity measured in Si/SiO 2 structures at 300 K (77 K). The saturation velocity is measured to be only 5% higher than in bulk Si, at both 300 and 77 K, but appears at a lower electric field. The effect of the enhanced transport properties in modulation-doped Si/SiGe on device design and performance is investigated.