Depth profiling of ultrashallow B implants in silicon using a magnetic-sector secondary ion mass spectrometry instrument

A Cameca IMS-4f secondary ion mass spectrometry instrument has been applied to the study of the diffusion of ultralow energy B implants in crystalline silicon. Several analyses on sub-keV B implants have been performed by usi ng low energy O-2(+) beams both before and after thermal annealing. The lim its and the accuracy of the technique are discussed. It is shown that a 1.5 keV beam provide he depth resolution needed to accurately characterize, be yond the equilibrium depth (similar to 5 nm), a 500 eV B implant. This meas urement protocol provides at the same time a significantly low detection li mit (1X10(15) at/cm(3)) and a very fast sputter rate (25 nm/min), necessary to characterize deep diffused profiles. Several artifacts are discussed, w ith emphasis to these affecting the tail region of the profiles. (C) 2000 A merican Vacuum Society. [S0734-211X(00)08201-9].