Light-Induced Voltage Alteration (LIVA)
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The lasers with 1340 nm wavelength eliminate the LIVA (light-induced voltage alteration) signal because the energy of the photons is below that of the Si (silicon) indirect band-gap. The photocurrent effects from e-h (electron-hole) pair generation by the 1064 nm laser used in LIVA produce signals 1 to 2 orders of magnitude larger than the SEI and TIVA signals so that the 1064 nm laser should be avoided in SEI and TIVA measurements. Note that some lasers with 1340 nm wavelength still contain a weak intensity (e.g. < 1%) of light with 1047 nm wavelength; therefore, a long wavelength pass filter needs to be placed in the beam path in order to eliminate the unwanted LIVA signals.

LIVA has not been the common method in failure analysis since the LIVA laser can induce electron and hole pairs in silicon (Si) bulk, which can induce large noise. This noise may cover up the useful signal, which limits the usage of LIVA [1].

 

 

 

 

 

 

 

 

 

 

 

[1] Lawrence C. Wagner, “Failure Analysis of Integrated Circuits: Tools and Techniques,” pp. 66-82, 1999. ISBN-10/ASIN: 0412145618, ISBN-13 / EAN: 9780412145612

 

 

 

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