Lateral gettering of iron by cavities induced by helium implantation in silicon

Lateral gettering has been studied by introducing cavities in the periphery of large active devices. Cavities were induced by helium implantation foll owed by a thermal treatment on samples previously contaminated by iron. Tho se cavities are known to be efficient to trap metallic impurities in silico n by chemisorption. The iron distribution in samples of 6x6 mm(2) area has been monitored by measuring current versus voltage characteristics and inte rstitial iron concentrations by deep level transient spectroscopy on Schott ky diodes uniformly distributed. A symmetrical iron distribution has been o bserved with a decreasing concentration close to the gettering region. This lateral gettering is enhanced with increasing thermal budget. Extensions o f several millimeters can be obtained allowing applications in power device technology. (C) 2000 American Institute of Physics. [S0021-8979(00)03022-X ].