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Amorphous vanadium oxide (VO 2 ) films deposited by atomic layer deposition (ALD) were crystallized with an ex situ anneal at 660–670 °C for 1–2 h under a low oxygen pressure (10 −4 to 10 −5 Torr). Under these conditions the crystalline VO 2 phase was maintained, while formation of the V 2 O 5 phase was suppressed. Electrical transition from the insulator to the metallic phase was observed in the 37–60 °C range, with an R OFF /R ON ratio of up to about 750 and ΔT C ≅ 7–10 °C. Lateral electric field applied across two-terminal device structures induced a reversible phase change, with a room temperature transition field of about 25 kV/cm in the VO 2 sample processed with the 2 h long O 2 anneal. Both the width and slope of the field induced MIT I-V hysteresis were dependent upon the VO 2 crystalline quality. [ABSTRACT FROM AUTHOR]

Studies of diamond material for thermal management are reported for a nominally 1-µm thick layer grown on silicon. Thickness of the diamond is measured using spectroscopic ellipsometry. Spectra are consistently modeled using a diamond layer taking into account surface roughness and requiring an interlayer of nominally silicon carbide. The presence of the interlayer is confirmed by transmission electron microscopy. Thermal conductivity is determined based on a heater which is microfabricated followed by back etching to produce a supported diamond membrane. Micro-Raman mapping of the diamond phonon is used to estimate temperature rise under known drive conditions of the resistive heater. Consistent values are obtained for thermal conductivity based on straightforward analytical calculation using phonon shift to estimate temperature and finite element simulations which take both temperature rise and thermal stress into account. [ABSTRACT FROM AUTHOR]