Measurement of band offsets in Si/Si12xGex and Si/Si12x2yGexCy heterojunctions
نویسندگان
چکیده
Realization of group IV heterostructure devices requires the accurate measurement of the energy band offsets in Si/Si12xGex and Si/Si12x2yGexCy heterojunctions. Using admittance spectroscopy, we have measured valence-band offsets in Si/Si12xGex heterostructures and conduction-band and valence-band offsets in Si/Si12x2yGexCy heterostructures grown by solid-source molecular-beam epitaxy. Measured Si/Si12xGex valence-band offsets were in excellent agreement with previously reported values. For Si/Si12x2yGexCy our measurements yielded a conduction-band offset of 100611 meV for a n-type Si/Si0.82Ge0.169C0.011 heterojunction and valence-band offsets of 118612 meV for a p-type Si/Si0.79Ge0.206C0.004 heterojunction and 223620 meV for a p-type Si/Si0.595Ge0.394C0.011 heterojunction. Comparison of our measured band offsets with previously reported measurements of energy band gaps in Si12x2yGexCy and Si12yCy alloy layers indicates that the band alignment is type I for the compositions we have studied and that our measured band offsets are in quantitative agreement with these previously reported results. © 1997 American Vacuum Society. @S0734-211X~97!07204-1#
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