Involvement of iron-phosphorus complexes in iron gettering for n-type silicon

Abstract

Mechanisms for phosphorus (P) diffusion gettering (PDG) for iron are supplemented by possible formation of iron-phosphorus complexes in heavy P-doped region. Existence of such complexes was recently reported based on the results of electron-spin resonance investigations. DLTS measurements suggest a high probability for the formation of iron-phosphorus complexes in n-type silicon in the presence of vacancies and/or vacancy-phosphorus pairs. On the other hand, recent theoretical calculations predict formation of negatively charged vacancy-phosphorus pairs in the heavily P-doped region of silicon during PDG. These facts indicate on possibility to explain the high efficiency of the PDG process for iron by assuming formation of iron-phosphorus complexes in the heavy P-doped region of silicon. Possible advantages of application of hydrogen or nitrogen assisted PDG are considered. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.