DEEP LEVELS IN HEAT-TREATED AND CF-252-IRRADIATED P-TYPE SILICON SUBSTRATES WITH DIFFERENT OXYGEN-CONTENT

The first results are presented of a deep-level transient spectroscopy (DLTS) study of deep levels in p-type silicon wafers with different oxygen contents and thermal pretreatments. The DLTs results are correlated with those of a structural characterization using cross-sectional transmission electron microscopy (TEM). The silicon oxide precipitate density and distribution correlates with the occurrence of minority carrier traps in the substrate. After irradiation with the fission products of a Cf-252 source, an order of magnitude increase of the leakage current is observed. At the same time, new DLTs peaks are introduced. While the creation of the divacancy-related centre (V2) is not affected by the presence and the status of oxygen, this is not the case for the second dominant peak related to an interstitial carbon-interstitial oxygen complex (C(i)O(i)) in p-type Czochralski substrates. In general the concentration of this trap scales with the residual interstitial oxygen content.