Boron diffusivity

Boron and carbon form one compound, boron carbide [12069-32-8] B C, although excess boron may dissolve ia boron carbide, and a small amount of boron may dissolve ia graphite (5). Usually excess carbon appears as graphite, except for the special case of boron diffused iato diamonds at high pressures and temperatures, eg, 5 GPa (50 kbar) and 1500°C, where boron may occupy both iaterstitial and substitutional positions ia the diamond lattice, a property utilized ia synthetic diamonds (see Carbon, diamond, synthetic). 

The emphasis in Australia and New Zealand is on treating permeable pine, but diffusion treatments are effective with impermeable green hardwoods and softwoods such as hemlock and spruce. In tropical countries boron diffusion offers many advantages no health hazard to operators, simple technology and the ability to treat local timbers locally. The major disadvantage is the stock holding period for diffusion and subsequent air-drying. 

Vinden P and Drysdale J (1990). Thickened boron "diffuse - a new approach to a traditional treatment. What s New in Forest Research No. 193. New Zealand Ministry of Forestry, Forest Research Institute... 

Figure 3.8 An illustration of the boron etch stop in the fabrication of a nozzle [26] (a) oxidation (b) lithography and development (c) boron diffusion (d) anisotropic etching ...

Boron diffusion leads to the formation of according to the reaction scheme... 

The process starts with a pressed powder mixture of one or more binary borides of M -type metals and the metals required for the constituent of the ternary phase and for the binder phase. This method enables the fabrication of tailored M -M -solid solutions in the ternary boride as well as allows the introduction of high-performance Fe- or Ni-based alloys with exceptional properties. The metal powders are usually atomized alloys but may also consist of powder blends of the particular elements of interest. In Fig. 113 [360] the reaction process is schematically summarized showing the M alloy denoted as metal . In principle, the first step is the boronization of the powder particles by boron diffusion... 

To realize the appropriate scheme for the enhanced sensitivity, it is important to note the basic properties of a piezoresistive cantilever for surface stress sensing [3]. One notable parameter is piezocoefBcient. P-type piezoresistors created by boron diffusion onto a single-crystal silicon (100) surface can be effectively utilized because of its high piezocoefficient [30-32]. Plain stress (i.e., = 0) is assumed because of the intrinsically... 

Most advantageously, the dielectric seal is formed by the low pressure chemical vapor deposition of a dielectric layer. The silicon is boron-doped silicon layer that is formed by boron diffusion (52). 

Boron diffusion in TaSi2 thin films was measured by using secondary ion mass... 

In contrast to the planar boron-diffusion silicon-based multielectrode arrays developed at the University of Michigan, three-dimensional electrode arrays are made through bulk micromachining, where the shanks are perpendicular to the wafer surface. These needle-bed arrays consist of sharpened tips, each of which is electrically isolated from its neighbors. Arrays at the University of Utah and the University of Twente were both based on silicon [28, 29]. 

Presence of an abnormal layer on the border of volume and near-surface regions. This layer is compensated p- and more often n-type in the case of A1 and Be diffusion. This layer is is low-doped and low-compensated (compared with neighboring ones) p-type in the case of boron diffusion (Fig. 8). 

Table 9 Ratios of Boron Diffusion Coefficients in Doped (N and Al) and Pure SiC...

Listing 12.8. Code segment for solving nonlinear diffusion PDE with parameters appropriate for Boron diffusion into Silicon. 

Listing 12.9. Code for solving for universal diffusion curves for transient diffusion into a semiconductor. Parameters are for Boron diffusion into Silicon. 

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