In this paper, we focus on critical issues directly related to the viability of carbon nanotube-based nanoelectromechanical switches, to perform their intended functionality as logic and memory elements, through assessment of typical performance parameters with reference to complementary metal-oxide-semiconductor devices. A detailed analysis of performance metrics regarding threshold voltage control, static and dynamic power dissipation, speed, and integration density is presented. Apart from packaging and reliability issues, these switches seem to be competitive in low power, particularly low-standby power, logic and memory applications.

We report on materials and device characterization of polycrystalline HfO 2 gate dielectrics grown by atomic layer deposition (ALD) at 600 • C on strained-Si and strained-SiGe layers. No change in the diffusion profile of Hf into the Si substrate was observed for temperatures in the range 900-1100 • C for 20 min. The strain status in the Si layer remained unaltered after HfO 2 deposition and an interface state density of ∼1 × 10 11 cm −2 eV −1 was obtained for the thicker HfO 2 films. The breakdown fields were in the range 2-5 MV cm −1 , which is high compared to HfO 2 films grown at higher temperatures. The leakage current was reduced by more than five orders of magnitude for the thin HfO 2 with an EOT of 1.25 nm and ultra-thin cap (2.5-3 nm) layers on Si 0.77 Ge 0.23 /Si, though high interface state densities (∼1 × 10 12 cm −2 eV −1 ) were observed. The carrier transport through these HfO 2 films was found to follow Frenkel-Poole emission over a wide range of applied gate voltages.

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