Influence of Crystal-Originated “Particle” Microstructure on Silicon Wafers on Gate Oxide Integrity

Abstract

To clarify the influence of crystal-originated “particles” (COPs) on gate oxide integrity (GOI), a new GOI evaluation method has been developed. This method compares the GOI of a metal oxide silicon (MOS) capacitor which includes a COP with a MOS capacitor that is COP-free by measuring the capacitors' I–V characteristics. Furthermore, to study the relationship between the shape of COP and GOI, the COP microstructure on the wafers was observed by atomic force microscopy (AFM) in the as-received state, after NH 4 OH/H 2 O 2 /H 2 O (SC-1) cleaning, high temperature annealing and repolishing. It was found that the presence of COP was the main cause of GOI failure and also that the shape of COP was closely related to the GOI yield. The microstructure of the original COP in a crystal is concluded to be an octahedral void and the same as an IR scattering defect.