Ultraviolet thermal processing

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Ultraviolet thermal processing or UVTP is the name given to the process of using ultraviolet light to stabilize dielectric films used to insulate semiconductors.

Dielectric electrically poorly conducting or non-conducting, non-metallic substance of which charge carriers are generally not free to move

A dielectric is an electrical insulator that can be polarized by an applied electric field. When a dielectric is placed in an electric field, electric charges do not flow through the material as they do in an electrical conductor but only slightly shift from their average equilibrium positions causing dielectric polarization. Because of dielectric polarization, positive charges are displaced in the direction of the field and negative charges shift in the opposite direction. This creates an internal electric field that reduces the overall field within the dielectric itself. If a dielectric is composed of weakly bonded molecules, those molecules not only become polarized, but also reorient so that their symmetry axes align to the field.

Description

Semiconductor films need low dielectric constants (k-values) for optimal thermal conductivity, to ensure semiconductor scaling. Newer dielectric films used to insulate modern chips can be easily damaged, causing them to lose their insulating capacity. Specialized treatments applied with ultraviolet light improve chip performance. [1] Tungsten halogen lamps are the sources used for traditional rapid thermal processing. [2] [3]

A semiconductor material has an electrical conductivity value falling between that of a conductor, such as metallic copper, and an insulator, such as glass. Its resistance decreases as its temperature increases, which is behaviour opposite to that of a metal. Its conducting properties may be altered in useful ways by the deliberate, controlled introduction of impurities ("doping") into the crystal structure. Where two differently-doped regions exist in the same crystal, a semiconductor junction is created. The behavior of charge carriers which include electrons, ions and electron holes at these junctions is the basis of diodes, transistors and all modern electronics. Some examples of semiconductors are silicon, germanium, gallium arsenide, and elements near the so-called "metalloid staircase" on the periodic table. After silicon, gallium arsenide is the second most common semiconductor and is used in laser diodes, solar cells, microwave-frequency integrated circuits and others. Silicon is a critical element for fabricating most electronic circuits.

The thermal conductivity of a material is a measure of its ability to conduct heat. It is commonly denoted by , , or .

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References

  1. Gupta, Nishant (December 2012). "Photo-thermal Processing of Semiconductor Fibers and Thin Films". All Dissertations. clemson.edu. Bibcode:2012PhDT.......211G . Retrieved 2016-05-03.
  2. Singh, R.; Cherukuri, K. C.; Vedula, L.; Rohatgi, A.; Narayanan, S. (1996-05-13). "Low temperature shallow junction formation using vacuum ultraviolet photons during rapid thermal processing". Applied Physics Letters. scitation.aip.org. 70 (13): 1700–1702. doi:10.1063/1.118674.
  3. Rapid Thermal Processing for Future Semiconductor Devices. Elsevier Science B.V. 2003-04-02. ISBN   9780080540269 . Retrieved 2016-05-04.