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The Deal-Grove model also fails for polycrystalline silicon ("poly-silicon"). First, the random orientation of the crystal grains makes it difficult to choose a value for the linear rate constant. Second, oxidant molecules diffuse rapidly along grain boundaries, so that poly-silicon oxidizes more rapidly than single-crystal silicon. [citation ...
The diffusion equation is a parabolic partial differential equation. In physics, it describes the macroscopic behavior of many micro-particles in Brownian motion , resulting from the random movements and collisions of the particles (see Fick's laws of diffusion ).
Diffusion current is a current in a semiconductor caused by the diffusion of charge carriers (electrons and/or electron holes). This is the current which is due to the transport of charges occurring because of non-uniform concentration of charged particles in a semiconductor.
In silicon (Si) the electron mobility is of the order of 1,000, in germanium around 4,000, and in gallium arsenide up to 10,000 cm 2 /(V⋅s). Hole mobilities are generally lower and range from around 100 cm 2 /(V⋅s) in gallium arsenide, to 450 in silicon, and 2,000 in germanium.
Thermal diffusivity of selected materials and substances [12]; Material Thermal diffusivity (mm 2 /s) Refs. Pyrolytic graphite, parallel to layers: 1,220: Diamond: 1,060–1,160: Carbon/carbon composite at 25 °C
This article describes how to use a computer to calculate an approximate numerical solution of the discretized equation, in a time-dependent situation. In order to be concrete, this article focuses on heat flow, an important example where the convection–diffusion equation applies. However, the same mathematical analysis works equally well to ...
Furnaces used for diffusion and thermal oxidation at LAAS technological facility in Toulouse, France. In microfabrication, thermal oxidation is a way to produce a thin layer of oxide (usually silicon dioxide) on the surface of a wafer. The technique forces an oxidizing agent to diffuse into the wafer at high temperature and react with it.
For air with a pressure of 1 bar, the Prandtl numbers in the temperature range between −100 °C and +500 °C can be calculated using the formula given below. [2] The temperature is to be used in the unit degree Celsius. The deviations are a maximum of 0.1% from the literature values.