Semiconductor-grade material

Dimethylcadmium has found use as a volatile source of Cd for metal organic chemical vapor deposition (MOCVD) production of cadmium-containing semiconductor thin films (qv) such as CdS, Cdi 2 Hg -Te, or Cdi 2 Mn -Te, as multiple quantum weU species (32). Semiconductor-grade material seUs for... 

EGA. The overall ion profiles for the semiconductor grade epoxy compounds are presented in Figures 9 and 10 for samples F(FR) and G(no-FR), respectively. Very little outgasslng is observed from these samples below 200 C, in marked contrast to the results obtained for the electrical grade epoxy samples. These data clearly reflect the effects of the more stringent processing controls employed in the production of the semiconductor grade materials. Also, because of the lower out-... 

Both for high-purity substances [617] and semiconductor-grade materials [618] up to 16 elements can be determined in 5N and 6N type samples. At high resolu-... 

The fourth example is the controlled solidification of germanium (or silicon) to produce semiconductor grade materials. The solid phase structure and composition depend strongly upon the interphase exchange processes which can enhance incorporation into the solid or into the liquid depending upon This example implicitly includes the production of most of the metallic structural materials. 

Si devices that function from —55 up to 125 °C became possible with the supply of high-purity semiconductor-grade material. In January 1954, BeU Labs chemist M. Tanenbaum fashioned the first Si transistor [5]. 

Antimonides of formulas CdSb and Cd2Sb2 have been reported. Both are usually prepared by direct union of the elements, the former is a hole-type semiconductor (9), with properties shown in Table 1, and finds use as a thermoelectric generator. Reagent-grade material costs 2.00/g in small lots. The band gap energy is 0.46 eV (2.70 J.m) (31) is 138 kj/mol (33.0 kcal/mol). Dicadmium triantimonideCd2Sb2, is a metastable, white... 

V semiconductor material (e.g. InGaAs semiconductor). Very high purity Ga and In are required for the manufacture of semiconductor grade GaAs substrate material and in the deposition of the III—V alloy epilayer structures on these substrates, for example for the manufacture of laser diodes. 

LED due to the direct bandgap of the Ill-nitrides. However, due to the lack of a native substrate for GaN, sapphire or SiC substrates were and are still used. The biggest use of semiconductor-grade SiC is still for LEDs, but now it serves the role as the substrate for the active GaN layer rather than both the substrate and the active layer. Today there are high-freqnency metal-semiconductor-field effect transistors (MES-EETs) offered commercially, as well as an emerging market for Schottky diodes made from SiC. We are still at the beginning of the SiC revolution, however, and the material s full potential has yet to be realized. 

The commercial potential of SiC has to date mainly been in the materials arena. SiC is used as substrate for LEDs made from GaN, which is the largest market of semiconductor-grade SiC. Recently Infineon launched its Schottky diode product... 

Elemental Analyses. The X-ray fluorescence measurements of Table 11 indicate a somewhat higher total Br content for the semiconductor grade novolac (sample F) than for the electrical grade (sample A). However, the data of Table 111 indicate halide concentrations in the extract that are an order of magnitude lower for the semiconductor grade novolac (sample G) is a factor of three material (sample F). 

Since no difference was found between FR and non-FR formulations in device aging studies, some other cause must account for the relatively early failures observed for devices molded in the electrical grade epoxy material and aged under bias at 200°C. These failures are attributed to chloride contamination present in the non-semiconductor grade epoxy resin. The extractable Cl concentration is a factor of four higher than Br, and this is correlated with a much higher concentration of CHoCl than CH Br in the EGA data below 200°C. The high Br concentration is also attributed to the... 

Semiconductor Grade Silicone-Epoxy. TGA, DSC, and EGA analyses revealed no difference between the FR and non-FR compounds below 200°C. The FR moieties again decomposed only in the temperature range above 350°C. There was very little Cl or Br in the aqueous extract, and no CH2CI or CH2Br was detected in the EGA product profiles. This shows the capability of material formulators to supply very clean semiconductor grade molding compounds. 

Semiconductor Grade Epoxies. As was the case for the semiconductor grade silicone-epoxy, there was no difference between FR and non-FR epoxies recorded by either DSC or EGA below 200°C. However, the nominally equivalent non-FR epoxy exhibited significantly lower thermal stability as indicated by the Isothermal TGA data. Furthermore, the aqueous extract of the non-FR compound contained more than twice as much Cl as the combined concentrations of Cl and Br in the FR epoxy. Although there have been no direct comparisons on device aging with these two epoxies, the above findings indicate that the FR compound, being cleaner and more thermally stable, could actually be the better material for encapsulation applications. 

A computational design procedure of a thermoelectric power device using Functionally Graded Materials (FGM) is presented. A model of thermoelectric materials is presented for transport properties of heavily doped semiconductors, electron and phonon transport coefficients are calculated using band theory. And, a procedure of an elastic thermal stress analysis is presented on a functionally graded thermoelectric device by two-dimensional finite element technique. First, temperature distributions are calculated by two-dimensional non-linear finite element method based on expressions of thermoelectric phenomenon. Next, using temperature distributions, thermal stress distributions are computed by two-dimensional elastic finite element analysis. 

Novolac resins are produced commercially from cresol mixtures that contain amounts of m-cresol and p-cresol isomers in varying proportions, depending on the specific application. The reaction proceeds with both metal cation and acid catalysis (Scheme 1.1) Because of strict guidelines for metallic contaminants in semiconductor grade process materials and chemicals, acid catalysis is employed in the synthesis of novolacs used in photoresist applications. In a typical commercial production process, a mixture of m- and p-cresol isomers, formaldehyde (most often in the form of formalin, a 35-40% aqueous solution of formaldehyde) and an oxalic acid catalyst are reacted, following the description of Pampalone ... 

Further uses of ICP-MS involve the analysis of semiconductor grade gases [75] and materials for interconnects (e.g., Cu). 

Argentine, M.D., Barnes, R.M. (1994) Electrothermal vaporization-inductively coupled plasma mass spectrometry for the analysis of semiconductor-grade organome-taUic materials and process chemicals. Journal of Analytical Atomic Spectrometry, 9,1371—1378. 

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