The families of 25 probands with sleepwalking and 27 probands with night terrors were studied. Eighty per cent of the sleepwalking pedigrees and 96 per cent of the night terror pedigrees included one or more individuals, other than the proband, who were affected by sleepwalking, night terrors, or both. Our data appear to fit a 'two threshold' multifactorial mode of inheritance. This finding supports the hypothesis that sleepwalking and night terrors share a common genetic predisposition, with sleepwalking being a more prevalent and less severe manifestation of the same substrate that underlies night terrors. Heritable factors predispose an individual to develop sleepwalking and/or night terrors, but expression of the trait may be influenced by environmental factors.

When As diffuses into Si, only a fraction of the As remains electrically active. Because of the importance of As as an emitter dopant, it is necessary to understand the nature of the inactive As and how it affects the solubility and diffusion of As+ ions. A model is proposed in which As+ diffuses via a simple vacancy mechanism while in quasiequilibrium with [VSiAs2] complexes. The flux of mobile monatomic As+ is modified according to the extent of [VSiAs2] complex formation. The structure of this defect and its formation energy (≈ 1.8 eV) are discussed. An effective diffusion coefficient is derived using this model: DAs=2DiCA /(1+8 K2′ CA3) where CA is the As+ concentration and K2′ is a collective parameter that depends upon As+ surface concentration and the diffusion temperature. Experimental verification of the correctness of this equation is given. The important results of this quantitative analysis show that DAs reaches a maximum value with increasing As concentration, and then decreases monotonically. The As concentration at which Dmax occurs is dependent upon the total As surface doping and the diffusion temperature. The ratio of total As to electrically active As+ decreases to a value of unity at 1300 °C. At 1250 °C it is shown that the solubility of As+ reaches a maximum value of 1.5 × 1021 atoms/cm3 in p-type Si and 1.2 × 1021 atoms/cm3 in n-type Si.

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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