Determination of Band Discontinuities in Silicon Heterostructures

Abstract

An estimation for the band offsets and the fundamental band gap has been presented for several silicon-germanium based heterostructures. This estimation considers both the band lineup at the interface of two different materials as well as strain effects. The valence and conduction band offsets in strained Si/SiGe, partially strain-compensated Si/SiGeC and Si/strained-Si heterostructures have been determined from quantum confinement of carriers measurements. High-frequency capacitance-voltage (C-V) profiling has been used to measure apparent carrier concentration and band offsets. Extracted experimental values are found to be in a good agreement with reported values obtained using other techniques.

Indexing terms:

• Strained layers
• Bandgap
• Conduction and valence band discontinuities
• Strained-Si
• Silicon-germanium
• Heterostructure MOSFET
• Gas source molecular beam epitaxy
• Band offset
• SiGeC