SiGe-free strained Si on insulator substrates were fabricated by wafer bonding and hydrogen-induced layer transfer of strained Si grown on bulk relaxed Si0.68Ge0.32 graded layers. Raman spectroscopy shows that the 49-nm thick strained Si on insulator structure maintains a 1.15% tensile strain even after SiGe layer removal. The strain in the structure is thermally stable during 1000 °C anneals for at least 3 min, while more extreme thermal treatments at 1100 °C cause slight film relaxation. The fabrication of epitaxially defined, thin strained Si layers directly on a buried insulator forms an ideal platform for future generations of Si-based microelectronics.
This paper studies the effect of the strained silicon thickness on the characteristics of strained silicon MOSFETs on SiGe virtual substrates. NMOSFETs were fabricated on strained silicon substrates with various strained silicon thicknesses, both above and below the strained silicon critical thickness. The low field electron mobility and subthreshold characteristics of the devices were measured. Low field electron mobility is increased by about 1.8 times on all wafers and is not significantly degraded on any of the samples, even for a strained silicon thickness far greater than the critical thickness. From the subthreshold characteristics, however, it is shown that the off-state leakage current is greatly increased for the devices on the wafers with a strained silicon thickness that exceeds the critical thickness. The mechanism of the leakage was examined by using photon emission microscopy. Strong evidence is shown that the leakage mechanism is source/drain electrical shorting caused by enhanced dopant diffusion near misfit dislocations.
We have investigated the energy loss rate of hot holes as a function of carrier temperature T C in p-type inverted modulation-doped ͑MD͒ Si/SiGe heterostructures over the carrier sheet density range (3.5-13)ϫ10 11 cm Ϫ2 , at lattice temperatures of 0.34 and 1.8 K. It is found that the energy loss rate ͑ELR͒ depends significantly upon the carrier sheet density, n 2D . Such an n 2D dependence of ELR has not been observed previously in p-type SiGe MD structures. The extracted effective mass decreases as n 2D increases, which is in agreement with recent measurements on a gated inverted sample. It is shown that the energy relaxation of the two-dimensional hole gases is dominated by unscreened acoustic phonon scattering and a deformation potential of 3.0Ϯ0.4 eV is deduced.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.