Effects of Thermocapillary Convection on the Growth Process in Industrial 8-inch Silicon Czochralski Growth

Czochralski (CZ) crystal growth process is a widely used technique in manufacturing of silicon crystals and other semiconductor materials. The ultimate goal of the IC industry is to have the highest quality substrates, which are free of point defect, impurities and micro defect clusters. The scale up of silicon wafer size from 200 mm to 300 mm requires large crucible size and more heat power. Transport phenomena in crystal growth processes are quite complex due to melt and gas flows that may be oscillatory and/or turbulent, coupled convection and radiation, impurities and dopant distributions, unsteady kinetics of the growth process, melt crystal interface dynamics, free surface and meniscus, stoichiometry in the case of compound materials. A global model has been developed to simulate the temperature distribution and melt flow in an 8-inch system. The present program features the fluid convection, magnetohydrodynamics, and radiation models. A multi-zone method is used to divide the Cz system into different zones, e.g., the melt, the crystal and the hot zone. For calculation of temperature distribution, the whole system inside the stainless chamber is considered. For the convective flow, only the melt is considered. The widely used zonal method divides the surface of the radiation enclosure into a number of zones, which has a uniform distribution of temperature, radiative properties and composition. The integro-differential equations for the radiative heat transfer are solved using the matrix inversion technique. The zonal method for radiative heat transfer is used in the growth chamber, which is confined by crystal surface, melt surface, heat shield, and pull chamber. Free surface and crystal/melt interface are tracked using adaptive grid generation. The competition between the thermocapillary convection induced by non-uniform temperature distributions on the free surface and the forced convection by the rotation of the crystal determines the interface shape, dopant distribution, and striation pattern. The temperature gradients on the free surface are influenced by the effects of the thermocapillary force on the free surface and the rotation of the crystal and the crucible.

Studies of the effects of industrial pollution in the lower Patapsco river area: 1. Curtis Bay Region 1941

Industrial effluents in the lower Patapsco area, which constitutes the navigable portion of the river and includes Baltimore Harbor, are many and include waste acid, distillery waters, tannery wastes and copper as (ferrous sulphate) from pigment and steel industries. (PDF contains 22 pages (2 on 1)

La reforma de los agregados monetarios en España, 1973-1992

Las dudas que aún se mantienen en pie tras varias décadas de debate teórico, los menores niveles de inflación existentes en la actualidad, las dificultades financieras planteadas por la persistencia de los tipos de interés en niveles altos durante muchos años, la necesidad de tasas mayores de crecimiento para reducir los niveles de desempleo y déficits públicos acumulados son razones que han ido inclinando la balanza hacia un menor peso de la política monetaria restrictiva en la combinación actual de instrumentos de política económica. Aunque no sin reticencias, la política antiinflacionista parece alejarse del planteamiento tradicional y situarse más en otros terrenos. El relevo lo están tomando la política salarial, la reforma del mercado laboral, la disminución del déficit público, la política de competencia y, en menor medida, la política industrial.

Un proyecto de investigación para el desarrollo de la competencia comunicativa oral de los futuros docentes

El V Seminario de "El aula como ámbito de investigación sobre la enseñanza y aprendizaje de la lengua" se celebró en la Universidad del País Vasco (UPV/EHU), dando continuidad a los seminarios ya celebrados en la Universidad Autónoma de Barcelona, en la Universidad de Valencia, en la Universidad de Valladolid y en la Universidad de Braga (Portugal).

Comunicaciones integradas feriales o como planificar con éxito una feria industrial

En este artículo se explica que la feria es una herramienta comercial utilizada habitualmente en el área de Marketing Industrial y que, a pesar de las ventajas que ofrece, recibe diversas críticas. Los frenos a su utilización están muy relacionados con la inversión que suponen tanto en recursos económicos como humanos. En definitiva, la feria es una herramienta con una gran potencialidad pero que requiere de un proceso de planificación riguroso y sistemático, con unos objetivos claros y definidos a partir de la estrategia de marketing global de la empresa. La aplicación del concepto de Comunicaciones Integradas Feriales pretende garantizar al expositor la optimización del esfuerzo realizado, maximizando el valor que las distintas herramientas de Marketing pueden aportar al programa ferial.

La competencia prosódica en la lectura en voz alta: análisis de los aspectos rítmicos

[EN] The current methodological tendencies give particular importance to the teaching of orality. Thus, several investigations have verified that reading aloud to children contributes positively to their cognitive development. However, in order to achieve the objective proposed with this type of reading, the prosodic aspect should not be forgotten. In spite of the few articles published up to now, the prosodic aspect is considered to be essential to provide a description of young people’s prosodic features when reading aloud, especially in order to create general rules that can be taught in our schools and universities. This paper is limited to the analysis of the types of rhythm, and for this, five informants have been selected and asked to read a text written in standard Basque.