Ring-Related Defects in MCZ Wafer Comparison by Electrical, Structural, and Device Properties

Abstract

ABSTRACTThermal cycles in advanced CMOS processing can nucleate an annular ring of oxygen precipitate-induced stacking faults (OSF-ring) via activation of bulk nuclei grown-in during the crystal pulling process. Because the OSF-ring can adversely affect device characteristics, it is important that substrates with OSF-ring characteristics be detected early in the process. Results are presented in this paper from a typical DRAM device which show that the ring can act either in a beneficial gettering mode or as a device-degrading zone, depending on the depth distribution of the OSF-ring defects and the background iron impurity concentration.