Si/Si1-xGexValence Band Discontinuity Measurements Using a Semiconductor-Insulator-Semiconductor (SIS) Heterostructure

Abstract

We have measured the valence-band dis- continuity of strained Si1-xGexon (100) unstrained Si using p-Si1-xGex/ si/p -Si1-semiconductor-insulator semiconductor (SIS) structures with Ge compositions in the range 10 < x < 25%. The epitaxial heterostructures were grown by ultra-high-vacuum chemical-vapor-deposition. A new data analysis procedure is proposed for extracting small ΔEc values out of the current-voltage characteristics of the SIS heterostructures as a function of temperature. Our data indicates that the valence band discontinuity between Si and Si1-xGexcan be approximated by ΔEc= 6.4x meV for 0 < x < 17.5%. © 1994 IEEE