Electrical characterization of ultra-thin gate oxides on Si/Si1-x-yGexCy/Si quantum well heterostructures

Ultra-thin gate oxides (<100 Angstrom) have been grown on partially strain- compensated Si/Si1-x-yGexCy/Si heterolayers (with different carbon concentr ations) using microwave O-2-plasma. A MOS capacitor has been used for the c haracterization of grown oxides. Capacitance-voltage (C-V) profiling has be en used to measure the apparent doping profile and thickness of the unconsu med Si-cap layer. A significant improvement in charge trapping properties, under Fowler-Nordheim (F-N) constant current stressing, has been observed f or low carbon containing films. The valence band offsets (Delta E-nu) of Si /Si0.69Ge0.3C0.01 and Si/Si0.685Ge0.3C0.015 heterostructures have been extr acted using the hole confinement characteristics. Incorporation of C lowers the valence band offset of the ternary alloy compared to those in Si1-xGex with the same Ge mole fraction.