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What is reverse antenna effect

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Amy25

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Hi ,could anyone explain the reverse antenna effect??
 

Its a semiconductor process failure mechanism the material is super heated in a plasma gas environment with charge injection. THere is one condition that results in a process failure that is counter-intuitive where the large area floating conductors discharge with less current injected rather than more. Hence "reverse" antenna effect.

9701024600_1445924937.jpg


More details https://en.wikipedia.org/wiki/Antenna_effect

Side notes
I have never worked with semiconductor processes. But I have seen charge clouds form over a ceramic disk drive head in vacuum head of Scanning Electron Microscope (SEM).​

When I raised the plate voltage a charge cloud appear over the surface that appear like low flying clouds on earth or a fog moving in. WHen I increased the filament current which heats the part up, more charge accumulates on the surface since it has nowhere to go in the insulator when saturated with charge ( like moisture accumulation into fog) Then when I zoomed into the surface up 50k x the charge density increased as the area of focus reduced and then a full discharge happened which burned a hole in the surface of the smooth ceramic.

INteresting but not the same as semi-conductor fabrication, but shows how charges can discharge in insulators that are doped to become semiconductors with hot plasma gas and plate current.
the same failure mechanism occurs in oil filled and dry power transformers from impurities and the smallest xxx nm sized voids or particles will zap causing a "partial discharge" and results in burning the molecules of oil around it to create Hydrogen which accumulates at a repetitive discharge rate. What the power transformer industry calls PD or Partial Discharge is similar to the "quasi-Discharge" phenomena in the semi-industry.

In semiconductors a polysilicon oxide has distributed zaps which make it leaky and shift the threshold of the resulting FET.


The Reverse effect is counter-intuitive at first because bigger "antenna" sized areas fail less frequently with more current per square nm (or cm) but only after a an over-charged previous process. Otherwise it fails with higher current than the process allows. There are many docs on the web to describe the design rule checks (DRC) to mitigate these issues.
 
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    Amy25

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