Deep electron traps in heteroepitaxial β-SiC films grown on Si(100) substrates by chemical vapor deposition were investigated. Capacitance deep level transient spectroscopy revealed the presence of several traps, the majority of which are rather process-induced as expected for a highly defective material such as β-SiC grown heteroepitaxially on Si. Samples of different origin as well as various surface treatments have been used to determine traps intrinsic to β-SiC heteroepitaxial material. Three main traps were detected, independently of the surface treatment, at 0.32, 0.52, and 0.56 eV below the conduction-band minimum. Comparison with theoretically predicted activation energies for the single native defects did not permit the assignment of the observed traps to any of these defects.
This paper presents the fabrication processes for micromachined millimetre-wave devices, on two different types of semiconductor substrates. The first process uses micromachining on high-resistivity 100 oriented silicon. A three-layer dielectric membrane, with a total thickness of 1.5 µm is used as support for the millimetre-wave structures. This process was used for the manufacturing of two coupled line filters, with central operating frequencies of 38 and 77 GHz, respectively. The second process is based on GaAs micromachining. For the first time, a 2.2 µm thin GaAs/AlGaAs membrane, obtained by molecular beam epitaxy growth and micromachining of semi-insulating 100 GaAs, is used as a support for millimetre-wave filter structures. Cascaded coplanar waveguide open-end series stubs filter type structures, with central frequencies of 38 and 77 GHz, respectively, were designed and manufactured on a GaAs micromachined substrate. 'On wafer' measurements for the filter structures were performed. Losses of less than 1.5 dB at 38 GHz and less than 2 dB at 77 GHz have been obtained for both the silicon as well as for the GaAs-based micromachined filters.
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.