Localization and detailed investigation of gate oxide integrity defects insilicon MOS structures

Grown-in crystal defects like crystal originated particles (COPs) in Czochr alski grown silicon wafers deteriorate the yield of metal oxide semiconduct or devices by causing dielectric breakdown of the insulating oxide layer. T he technique of lock-in IR-thermography is presented, which allows the loca lization of active gate oxide integrity (GOI) defects with a lateral resolu tion of about 10 mum as well as to make a full wafer image of electrically broken down GOI defects. Using this technique, the density and the distribu tion of GOI defects was determined across whole wafers. MOS structures with Si substrate materials with different COP densities and with various oxide thickness were analyzed. Single GOI defects were activated by a current li mited breakdown and localized with lock-in IR-thermography. Planar TEM spec imens were prepared and the defect origin was examined. (C) 2001 Elsevier S cience B.V. All rights reserved.