We approximate liquid water as a lone-pair amorphous semiconductor. Since electronic orbital times are short compared to the periods of atomic and molecular motion, properties dependent on electronic states can be interpreted to determine short-time intermediate range order. An anomalous temperature dependence of the Urbach exponential absorption edge for intramolecular electronic excitation is noted and interpreted in terms of the perturbation of the lone-pair valence band by hydrogen bonding. The extrinsic optical absorptions with I− and Br− doped water are observed to have Urbach tails. An approximate electronic band structure for pure and doped liquid water is presented.

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Introduction:We report measurements of the DC characteristics of sub-l00nm nMOSFETs that employ low leakage. ultra-thin gate oxides only 1 -2nm thick to achieve high current drive capability and transconductance. We demonstrate that ZDsctr=: 1.8mAIp.m can be achieved with a 60nm gate at 1.5V using a 1.3-1.4nm gate oxide with a gate leakage current less than 20r~AIp.m~. Furthermore, we find that ZDscrr deteriorates for gate oxides thicker or thinner than this.Fabrication: We have explored a gate stack consisting of l00nm of TEOS hard mask over 80nm of doped W.5, on 1 00nm of in-situ phosphorus-doped poly-crystalline silicon on gate oxides ranging in thickness from 1 -2nm thick on a ptype epitaxial silicon. Prior to the oxide growth, the substrates were stripped by immersion into a 15: 1 H 2 0: HF solution for only 5 seconds (to minimize surface roughness and pitting) and then subjected to a vapor phase clean in 10 Torr

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This paper describes the fabrication, and structural and electrical characterization of a new, aerosolnanocrystal floating-gate FET, aimed at non-volatile memory (NVM) applications.This aerosolnanocrystal NVM device features prograderase characteristics comparable to conventional stacked gate NVM devices, excellent endurance (>lo5 P/E cycles), and long-term non-volatility in spite of a thin bottom oxide (55-60A). In addition, a very simple fabrication process makes this aerosol-nanocrystal NVM device a potential candidate for low cost NVM applications.Introduction The memory operation of the aerosol-nanocrystal floating-gate FET depends on charge storage, similar to conventional stacked-gate NVM devices [l]. In a nanocrystal NVM device, however, charge is not stored on a continuous floating-gate poly-Si layer, but instead on a layer of discrete, crystalline Sinanocrystals [2-41. As compared to conventional stacked-gate NVM devices, nanocrystal chargestorage offers several potential advantages such as: (1) simple, low cost device fabrication (no dual-poly process complications); (2) better retention (resulting from Coulomb blockade and quantum confinement effects fS]), enabling thinner tunnel oxides and lower operating voltages; ( 3 ) improved anti-punchthrough performance (due to the absence of drain to floating gate coupling, thereby reducing drain induced punchthrough), allowing higher drain voltages during read-out, shorter channel lengths and, consequently, a smaller cell area; and (4) excellent immunity to stress induced leakage current (SILC) and defects due to the distributed nature of the charge storage in the nanocrystal layer. Device Fabrication Nanocrystal layer fabricationThis potential for cost reduction and improved device performance and reliability is, however, strongly dependent on the physical properties of the nanocrystal layer, such as the crystal size and size distribution, crystal areal density, layer co-planarity and uniformity, and crystal-to-crystal interaction (lateral conduction). In order to achieve the desired layer properties, a novel, three-step nanocrystal fabrication process has been developed (Fig. 1). In the first step, a nanocrystal silicon aerosol is generated by the pyrolysis of diluted silane at 950°C. Particles initially form by homogeneous gas-phase nucleation and grow by vapor deposition and coagulation. The coagulation has been reduced by quenching the aerosol with an ultrahigh-purity nitrogen flow.Silane concentration, furnace temperature and silane residence time have all been optimized in order to generate an aerosol of spherical, single crystalline nanocrystals (Fig. 2, inset) with well-controlled diameters (Fig. 3) as small as 3nm. In the second step, a 1.5-2nm high-quality thermal oxide shell is grown at 1000°C on the particles. This insulating shell reduces lateral crystal-to-crystal conduction in the nanocrystal layer. The oxidation step has the additional advantage of sharpening the