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Advanced defect and impurity diagnostics in silicon based on carrier lifetime measurements

: Warta, W.


Physica status solidi. A 203 (2006), Nr.4, S.732-746
ISSN: 0031-8965
ISSN: 1862-6300
ISSN: 1521-396X
ISSN: 1862-6319
Fraunhofer ISE ()

An overview is given on recent developments at Fraunhofer ISE in the field of diagnostic techniques based on carrier lifetime measurements. The status of the different lifetime spectroscopy methods and the diagnostic capabilities of infrared carrier lifetime imaging are outlined. A combination of short acquisition times with high spatial resolution and high dynamic range under (quasi-) steady-state conditions gives IR lifetime imaging a high potential for the application in material and process characterization. Measuring in the emission mode provides access to the temperature dependence of lifetime and thus spatially resolved temperature dependent lifetime spectroscopy. Images of injection dependent lifetimes may be measured. For the anomalous increase at low injection a modeling description was developed. Assuming carrier trapping as origin of the increase, spatially resolved trap parameter analysis is possible. A new approach to suppress the anomalous increase by the application of sub-bandgap light was demonstrated.