Hall Mobility in Chemically Deposited Polycrystalline Silicon
01 Oct 1971-Journal of Applied Physics (American Institute of Physics)-Vol. 42, Iss: 11, pp 4357-4365
TL;DR: In this article, the authors performed Hall mobility measurements on polycrystalline silicon films with and without doping impurities added during deposition or by diffusion from a doped vapordeposited oxide.
Abstract: Hall‐mobility measurements have been performed on polycrystalline silicon films deposited on a silicon oxide surface by the thermal decomposition of silane. Samples with doping impurities added during deposition or by diffusion from a doped vapor‐deposited oxide showed similar behavior. For both n‐type and p‐type samples approximately 5 μ thick, the mobility reached a maximum value of about 40 cm2/V sec at a free carrier concentration of about 1018 cm−3 and decreased for both higher and lower carrier concentrations. The observed Hall mobility was generally higher in p‐type samples than in n‐type samples. The decrease in observed mobility with decreasing carrier concentration is attributed to the effects of high resistivity space‐charge regions surrounding grain boundaries in the polycrystalline material. The mobility was seen to increase as the film thickness increased for samples with similar doping, indicating a more ordered structure in thicker films.
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TL;DR: In this article, Boron doses of 1×1012-5×1015/cm2 were implanted at 60 keV into 1-μm-thick polysilicon films and Hall and resistivity measurements were made over a temperature range −50-250 °C.
Abstract: Boron doses of 1×1012–5×1015/cm2 were implanted at 60 keV into 1‐μm‐thick polysilicon films. After annealing at 1100 °C for 30 min, Hall and resistivity measurements were made over a temperature range −50–250 °C. It was found that as a function of doping concentration, the Hall mobility showed a minimum at about 2×1018/cm3 doping. The electrical activation energy was found to be about half the energy gap value of single‐crystalline silicon for lightly doped samples and decreased to less than 0.025 eV at a doping of 1×1019/cm3. The carrier concentration was very small at doping levels below 5×1017/cm3 and increased rapidly as the doping concentration was increased. At 1×1019/cm3 doping, the carrier concentration was about 90% of the doping concentration. A grain‐boundary model including the trapping states was proposed. Carrier concentration and mobility as a function of doping concentration and the mobility and resistivity as a function of temperature were calculated from the model. The theoretical and ex...
2,657 citations
TL;DR: In this paper, the authors introduce the principles and present status of bulk nanostructured materials, then describe some of the unanswered questions about carrier transport and how current research is addressing these questions.
Abstract: Thermoelectrics have long been recognized as a potentially transformative energy conversion technology due to their ability to convert heat directly into electricity. Despite this potential, thermoelectric devices are not in common use because of their low efficiency, and today they are only used in niche markets where reliability and simplicity are more important than performance. However, the ability to create nanostructured thermoelectric materials has led to remarkable progress in enhancing thermoelectric properties, making it plausible that thermoelectrics could start being used in new settings in the near future. Of the various types of nanostructured materials, bulk nanostructured materials have shown the most promise for commercial use because, unlike many other nanostructured materials, they can be fabricated in large quantities and in a form that is compatible with existing thermoelectric device configurations. The first generation of these materials is currently being developed for commercialization, but creating the second generation will require a fundamental understanding of carrier transport in these complex materials which is presently lacking. In this review we introduce the principles and present status of bulk nanostructured materials, then describe some of the unanswered questions about carrier transport and how current research is addressing these questions. Finally, we discuss several research directions which could lead to the next generation of bulk nanostructured materials.
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TL;DR: A comparison study of high-k Dielectric Materials for OFETs using self-Assembled Monoand Multilayers and Inorganic-Organic Bilayers to study the properties of polymeric-Nanoparticle Composites.
Abstract: 2.2. Interface Trapping Effects 211 3. High-k Dielectric Materials for OFETs 212 3.1. Inorganic Dielectrics 212 3.1.1. Aluminum Oxide 213 3.1.2. Tantalum Oxide 215 3.1.3. Titanium Dioxide 216 3.1.4. Hafnium Dioxide 217 3.1.5. Zirconium Dioxide 218 3.1.6. Cerium Dioxide 218 3.2. Organic Dielectrics 218 3.2.1. Polymer Dielectrics 218 3.2.2. Self-Assembled Monoand Multilayers 225 3.3. Hybrid Dielectrics 227 3.3.1. Polymeric-Nanoparticle Composites 227 3.3.2. Inorganic-Organic Bilayers 232 3.3.3. Hybrid Solid Polymer Electrolytes 235 4. Summary 235 5. Acknowledgments 236 6. References 236
788 citations
TL;DR: In this article, the transport properties of polycrystalline silicon films are examined and interpreted in terms of a modified grain-boundary trapping model, based on the assumption of both a δ-shaped and a uniform energy distribution of interface states.
Abstract: The transport properties of polycrystalline silicon films are examined and interpreted in terms of a modified grain‐boundary trapping model. The theory has been developed on the assumption of both a δ‐shaped and a uniform energy distribution of interface states. A comparison with experiments indicates that the interface states are nearly monovalent and peaked at midgap. Their density is 3.8×1012 cm−2, in accordance with carrier‐lifetime measurements performed on CVD films.
673 citations
TL;DR: In this article, the effect of thermal annealing on implanted and unimplanted CdSe TFTs has been studied and the model appears to give a general description of the conductivity behavior in polycrystallin...
Abstract: CdSe thin film transistor (TFT) structures which have been ion implanted with 50 keV 52Cr, 50 keV 27Al, or 15 keV 11B have a very steeply rising conductivity above some threshold dose and exhibit modulated transistor characteristics over certain ranges of implant dose, even though there is no thermal annealing during or after ion implantation. These results are interpreted using a model based on grain boundary trapping theory. The dependence of leakage current on implant dose, and of drain current (at a fixed dose) on gate voltage are described very well by this model, when the drain voltage is very small. Using this simple model, the important parameters of the polycrystalline CdSe film, namely the trap density per unit area in the grain boundary, the donor density, grain size, and electron mobility can be deduced. The effect of thermal annealing on implanted and unimplanted CdSe TFT’s has also been studied and the model appears to give a general description of the conductivity behavior in polycrystallin...
573 citations
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TL;DR: In this article, the authors measured the effective mobility, field effect mobility, Hall mobility, and carrier density of Si as a function of field perpendicular to the surface, and reported that at all temperatures from 42 to 300, at least one maximum in the mobility was observed.
Abstract: Measurements of the effective mobility, field effect mobility, Hall mobility, and carrier density of Si as a function of field perpendicular to the surface are reported At all temperatures from 42 to 300\ifmmode^\circ\else\textdegree\fi{}K, at least one maximum in the mobility was observed The temperature dependence is reported for different fields At room temperature, a single maximum in the mobility was observed close to the threshold for inversion As the temperature was lowered, this peak increased At temperatures near 80\ifmmode^\circ\else\textdegree\fi{}K, it then decreased Another maximum appeared at about 100\ifmmode^\circ\else\textdegree\fi{}K at higher fields; it increased as the temperature was lowered An anomalous shift in the conductance threshold between 773 and 42\ifmmode^\circ\else\textdegree\fi{}K is reported and is correlated with the charge in the oxide Effects of substrate bias are reported Some comments are made on possible scattering mechanisms The effect of interface states was measured and their density near the conduction band is reported
272 citations
200 citations
TL;DR: In this article, the potential of a line of point charges is investigated in terms of mathematical functions related to the potentials of point charge potentials, and the use of these functions is illustrated by applications to semiconductor resistivity measurements and to calculations of the base resistance of transistors.
Abstract: Tables and charts are given of mathematical functions related to the potential of a line of point charges. The use of these functions is illustrated by applications to semiconductor resistivity measurements and to calculations of the base resistance of point-contact transistors.
199 citations
TL;DR: In this article, the anneal behavior of layers implanted with dopants from column III (B, Al, Ga, and Tl) and column V (As, Sb, and Bi) in silicon substrates has been investigated.
Abstract: The anneal behavior of layers implanted with dopants from column III (B, Al, Ga, and Tl) and column V (As, Sb, and Bi) in silicon substrates has been investigated. The ranges of implant conditions were energy 20–50 keV, dose 1013–1015/cm2, and substrate temperature 23°–500°C. Hall‐effect and sheet resistivity measurements were used to determine the effective number of carriers/cm2 (Ns)eff and the effective mobility μeff. Analysis of nonuniform distributions of carrier densities and mobilities on these measurements shows that the values of (Ns)eff and μeff can be misleading unless the effect of the depth distributions is allowed for. These distributions have been determined in some cases by the use of layer removal techniques combined with Hall‐effect and sheet resistivity measurements. We find in well‐annealed implanted samples that the dependence of the mobility on carrier density follows that determined for bulk silicon. In many cases deviation from this relation can be accounted for on the basis of com...
136 citations