Dopants in semiconductors

The method is essentially non-destructive, although in some circumstances a target may suffer radiation damage. For example the lattice site position of some dopants in semiconductors can be influenced by RBS analysis. With a typical analysis time of less than 30 min, it is a relatively quick method. Its most important characteristic is... 

Fe, on the other hand, has been used directly in PC processes as a dopant in semiconductors, in particular for Ti02. The results seem to be somewhat contradictory nonetheless. These doped catalysts have been tested in the PC reactions of short-chain carboxylic acids such as maleic, formic, and oxalic acids, among others. 

The development of the neutron depth profiling technique has been motivated by the importance of boron in both optical and microelectronic materials. Boron is widely used as a p-type dopant in semiconductor device fabrication and in the insulating oxide barriers applied as an organometallic or in vapor phase deposition glasses. 

The diffusion of dopants in semiconductors has been briefly discussed in Sect. 2.1.3. At an atomic scale, the diffusion of a FA in a crystal lattice can take place by different mechanisms, the most common being the vacancy and interstitial mechanisms in silicon and germanium (see for instance [25]). The interstitial/substitutional or kick-out mechanism, which is an interstitial mechanism combined with the ejection of a lattice atom (self-interstitial) and its replacement by the dopant atom is also encountered for some atoms like Pt in silicon. 

The value of the diffusion coefficients of impurities and dopants in semiconductors can be modified by the presence of compensating impurities or of crystal dislocations so that the interpretation of diffusion measurements requires some judgment, ft must also be mentioned that as the diffusing species can be ions, the diffusion coefficient can be modified by an electric field. 

Carbon tetrachloride finds different industrial uses as solvent, as dopant in semiconductor industries, as raw material [1-3]. 

SIMS is used for quantitative depth profile determinations of trace elements in solids. These traces can be impurities or deliberately added elements, such as dopants in semiconductors. Accurate depth prohles require uniform bombardment of the analyzed area and the sputter rate in the material must be determined. The sputter rate is usually determined by physical measurement of the crater depth for multilayered materials, each layer may have a unique sputter rate that must be determined. Depth prohle standards are required. Government standards agencies like NIST have such standard reference materials available for a limited number of applications. For example, SRM depth profile standards of phosphorus in silicon, boron in silicon, and arsenic in silicon are available from NIST for calibration of SIMS instmments. P, As, and B are common dopants in the semiconductor industry and their accurate determination is critical to semiconductor manufacture and quality control. 

Arsenic is an element with the symbol As and the atomic number 33. It can occur as a pure element but is most often found in minerals containing sulfur and metals. Arsenic can exist in different structural forms (allotropes). However, gray arsenic is the most common. It is a metalloid that is brittle and a bit shiny. See Fig. 5 [25]. This form has metallic properties and has been used in industry to strengthen alloys of copper and lead. Arsenic is also a common n-type dopant in semiconductor electronic devices (example gallium arsenide is a semiconductor). Over the years arsenic and its compounds were used in the production of products like pesticides, insecticides, and treated wood items. However, because of its toxicity and harmful effects to humans, arsenic s applications have decreased. 

An alternative interpretation of electric conduction in solids is based on the fact that charge transfer is possible only in non-ideal lattices. The solid must have crystallographic defects. Foreign atoms as dopants in semiconductors can be considered as a defect itself, but not as the only one. 

EEL spectra can also provide information on electronic band structures and core losses can be used to chemically identify different atomic species. The high current and small probe size obtainable with aberration corrected STEM instrumentation has enabled atomic resolution elemental mapping of a wide range of materials. The sensitivity of the technique has allowed the chemical identification of single atoms including dopants in semiconductor quantum dots (Fig. 4). ... 

Also suitable for study are dopants in semiconductors and local structures in semiconductor lasers. 

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