Gas source molecular beam epitaxy grown strained-Si films on step-graded relaxed Si1−xGexfor MOS applications

Gas source molecular beam epitaxy has been employed for the growth of a high quality strained-Si layer on a completely relaxed step-graded Si1−xGexbuffer layer. As-grown strained-Si layers have been characterized using secondary ion mass spectroscopy, Rutherford backscattering spectroscopy, atomic force microscopy, and spectroscopic ellipsometry for the determination of composition, thickness, crystalline quality, and surface roughness. Heterojunction conduction and valence band offsets (ΔEc, ΔEυ) of strained-Si/SiGe heterostructure have been determined from measured threshold voltages of a strained-Si channel p-metal oxide semiconductor field effect transistor (MOSFET) fabricated using grown films. MOS capacitance-voltage profiling has been employed for the extraction of strained-Si layer thickness and apparent doping profile in the device.