The precise control of ion implants for threshold voltage adjustment requires formation of ultra-shallow electrically active carrier profiles, which begin at the Si-SiO2 interface. Obtaining accurate and precise carrier density profiles near the interface with metal-oxide-semiconductor capactiance-voltage (MOS C-V) requires special data acquisition, numerical analysis, and surface corrections. These methods, when applied to C-V data collected with a unique, highly repeatable mercury (Hg) probe, provide rapid data acquisition and analysis for threshold adjust implant control in a production environment. Pulsed MOS C-V measurements were used to profile implanted layers with peak carrier densities of approximately 10(17) cm-3, located 15 nm from the Si-SiO2 interface.