High sputter rate SIMS analysis of insulators used in microelectronics and lightwave applications.

The capability to obtain concentration depth profiles in insulators at high sputter rates has been used to characterize SiO sub 2, Si sub 3 N sub 4, borophosphosilicate glass (BPSG), and LiNbO sub 3. Analyses were made on a Perkin Elmer PHI-6300 with an O sub 2 sup + primary beam utilizing an electron beam for charge neutralization. Sputter rates in excess of 1.0 nm/s were obtained without the use of conductive screens or coatings. The important parameters for charge neutralization were found to be the angle of incidence of the primary beam, the electron current density, and the ability to precisely aim the electron beam to coincide with the area sputtered by the ion beam. The quantitation of several elements including B, P, and Cl in SiO sub 2 was achieved with the use of calibrating ion implants. The relative ion yields for several atomic and molecular ions were also determined and the data used to resolve several common mass interferences.