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Saturday, April 19, 2014

#285 Silicon and iron

Due to the way chemicals used in silicon processing are manufactured and handled, trace contamination of Si wafers with iron (Fe) is essentially unavoidable. Also, iron finds its way into Si wafer during conventional single-crystal growth process. More serious of the problem in terms of the potential harm are occasional malfunctions/degradation of the stainless steel gas-delivery systems which result in wafer contamination with Fe above acceptable limits.


Just like in the case of most metallic contaminants, the adverse effect of iron is triggered by the elevated temperature treatments of Si wafer during device processing. Unlike copper, iron is not a fast diffusant in silicon. Once in Si, however, iron will have an adverse impact on device performance by forming defects acting as carrier recombination centers. If allowed on the wafer surface during thermal oxidation for instance, Fe will promote formation of interface traps at the Si-SiO2 interface.


Either way, there is nothing good that results from Fe interactions with Si wafer. Fortunately, iron contamination of silicon and silicon device manufacturing environment is much more effectively prevented now than it used to be in the past.

Posted by Jerzy Ruzyllo at 09:39 AM | Semiconductors | Link is the personal blog of Jerzy Ruzyllo. With over 35 years of experience in academic research and teaching in the area of semiconductor engineering (currently holding position of a Distinguished Professor of Electrical Engineering and Professor of Materials Science and Engineering at Penn State University), he has a unique perspective on the developments in this progress driving technical domain and enjoys blogging about it.

With over 2000 terms defined and explained, Semiconductor Glossary is the most complete reference in the field of semiconductors on the market today.

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