Rectifiers junction temperatures

A.6.3 Determine the Junction Temperature of a Rectifier with a Known Lead Temperature... 

Robert B. Campbell and Hung-Chi Chang, Silicon Carbide Junction Devices R.E. Enstrom, H. Kressel, and L. Krassner, High-Temperature Power Rectifiers of GaAs P,... 

Power supply capabilities for thermoelectric coolers range from the simple open-loop direct current supply with a switch to sophisticated feedback systems with close temperature regulation and fast response. The only limitation on the supply is that ripple be maintained at a point lower than 10 to 15%. Open-loop systems will generally contain a transformer, rectifiers, choke, and chassis with heat sink for the rectifiers. In feedback systems, a thermistor is used to sense temperature at the cold junction. This signal is compared with the desired temperature setting to obtain an error signal. 

Very recently, experimentalists have succeeded in developing template-based chemical vapor deposition CVD),[30] and pyrolysis of organometallic precursor with nickelocene and thiophene techniques[31] that allows for the reproducible and high-yield fabrication of carbon nanotube Y-junctions.[30, 31] The conductance measurements on these Y-j unctions have shown intrinsic rectifying I-V behavior at room temperature.[31, 32)... 

Concept Check 18.8 Would you expect increasing temperature to influence the operation of p-n junction rectifiers and transistors Explain. 

Thin film metallization is often used to establish contact with a surface. In many cases, the contact involves reactions that form a layer of compound material between the metallization and the surface. For instance, in the deposition of platinum on silicon, a layer of platinum silicide is formed. The contact resistance involves not only the resistance between the metallization and the surface but the effect of the reaction layer, which can be a high resistivity material or present a potential barrier. In the extreme, the junction may be rectifying (i.e. current can flow in one direction easily but in the other with difficulty). The metallization material can also alloy with the substrate material. For example, gold will diffuse into silicon to some extent and the higher the temperature, the higher the solubility of gold in the silicon. 

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