Optical Beam Induced Current Technique as a Failure Analysis Tool of EPROMs

Jun SATOH  Hiroshi NAMBA  Tadashi KIKUCHI  Kenichi YAMADA  Hidetoshi YOSHIOKA  Miki TANAKA  Ken SHONO  

IEICE TRANSACTIONS on Electronics   Vol.E77-C   No.4   pp.574-578
Publication Date: 1994/04/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on LSI Failure Analysis)
data retention failure,  EMS,  EPROM,  failure analysis,  OBIC,  

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The mechanism for data retention failure of EPROM has been investigated by the Optical Beam Induced Current(OBIC) technique. It was found that the data of failure cells were changed from '1' to '0' during read-mode by laser irradiation by OBIC. The data in good cells was not changed. This result suggests the effective barrier height between Si and SiO2 is being lowered. In addition, the cross section technique revealed that gate electrode and gate oxide were exposed due to lack of dielectric layers. This defect seemed to be the cause of the barrier height lowering. The OBIC technique not only gives the failure location but a detailed information of the failure mechanism. We found that OBIC technique is a very powerful tool for the analysis of EPROM failure mechanisms. The usefulness of the Emission Micro Scope (EMS) technique is also discussed.