In this study, differential Hall measurement (DHM) was developed to measure the carrier profiles in phosphorus doped ultrashallow junctions (USJs). Experiments using uniform phosphorus profiles in silicon on insulator (SOI) wafers demonstrated that the growth rate of the native oxide strongly depends on the phosphorus doping level. Therefore, the thickness of native oxide was monitored by X-ray photoelectron spectroscopy
(XPS) to achieve nanometer depth resolution during DHM. The DHM method was applied to investigate the deactivation of phosphorus in laser annealed USJs. The DHM results indicate carrier profile redistribution near the surface due to uphill diffusion caused by phosphorus deactivation.