Correlation between threshold voltage and channel dopant concentration in negative-type metal-oxide-semiconductor field-effect transistors studied by atom probe tomography

The correlation between threshold voltage (V _T) and channel boron concentration in silicon-based 65 nm node negative-type metal-oxide- semiconductor field-effect transistors was studied by atom probe tomography (APT). V _T values were determined for one million transistors in a single chip, and transistors having a ±4σ deviation from the median V _T were analyzed using APT. V _T and the channel boron concentration were positively correlated. This is consistent with the relationship between the average boron concentration of wafers implanted with different channel doses and the median V _T of the million transistors. APT is suitable for the study of dopant-distribution-based device failure mechanisms.