EFFECTS OF IRON CONTAMINATION IN SILICON ON THIN OXIDE BREAKDOWN AND RELIABILITY CHARACTERISTICS

Effects of iron contamination on the breakdown and reliability charact eristics of thin silicon gate oxides are discussed, Gate oxide integri ty is measured for thermal oxides of 8, 10, 13 and 20 nm grown on sili con wafers intentionally contaminated with 10(10)-10(14) cm(-3) of iro n. Iron concentration in silicon is measured using surface photovoltag e (SPV) minority carrier lifetime analysis. The density of gate oxide weak spots as a function of iron concentration for the various oxide t hicknesses is reported. For 10 nm oxides, iron concentration cannot ex ceed 8 x 10(10) cm(-3) without severe degradation in oxide quality, Th e threshold contamination level for 20 nm oxides is 200 times higher