Grown-in oxide precipitate nuclei in Czochralski silicon substrates and their role in device processing

Using a method to study the grown-in defect density spectra in Czochralski silicon wafers, we elucidate the changes in the size distribution of grown- in oxide precipitate nuclei caused by thermal processing in a common comple mentary metal-oxide semiconductor device process. The first thermal step de termines which parts of the grown-in defects grow to large stable defects a nd how many harmful defects appear in the defect-denuded zone. The cooling rate of the crystal considerably influences the defect evolution during com plementary metal oxide semiconductor processing. The choice of appropriate silicon material for a device process or adjusting processing conditions to suit the material are important for defect generation during processing an d, consequently, also for device yield. (C) 1999 The Electrochemical Societ y. S0013-4651(97)12-044-4. All rights reserved.