A Site Specification Method of Gate Oxide Breakdown Spots by a New Test Structure of MOS Capacitors

Satoshi IKEDA  Hidetsugu UCHIDA  Norio HIRASHITA  

IEICE TRANSACTIONS on Electronics   Vol.E85-C   No.5   pp.1134-1137
Publication Date: 2002/05/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Microelectronic Test Structures)
MOS capacitor,  gate oxide,  OBIC,  breakdown spot,  XTEM,  

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A new test structure to specify accurately the position of gate oxide breakdown is proposed, which simply consists of a conventional polycrystalline Si gate MOS capacitor and Al dots array diagonally lined-up on the capacitor. Optical beam induced current microscope was used to discriminate the breakdown spot. Layout of the discriminated spot among the Al dot array accurately determined the breakdown position. A 5-nm-thick gate oxide breakdown spot determined by this method has been successfully investigated by cross-sectional transmission electron microscopy (XTEM). A series of site-specified XTEM studies reveal local melting of anode Si during the intrinsic dielectric breakdown. This test structure is practically useful for site-specified XTEM studies on process-induced degradation phenomena of thin gate oxides.