Silicon Ingot Lifetime Tester for Industrial Use

Research output: Contribution to conferencePaper


A specially designed lifetime measurement instrument has developed to characterize silicon ingots before they are subjected to expensive slicing and solar-cell processing, thereby saving needless processing costs of inferior materials in a solar-cell production line. The instrument uses the direct-current photoconductance decay (DC-PCD) method for linear detection of the transientphotoconductance signal and localized probing / illumination for necessary sensitivity on low resistivity and large samples. The instrument also has a compact and high-power laser diode as the light source, data averaging capability, a pneumatic ingot transport and probe positioning mechanism, and a user-friendly graphical interface for data acquisition/lifetime calculation/data storage/hardcopyfor factory-floor use with quick turnaround. A 3-dimensional finite-element analysis indicates that the as-cut surface finish is adequate for measuring the bulk lifetime on the oder of 50 or less. Measurement repeatability and clear distinction amoung different grades of feedstock materials have been demonstrated.
Original languageAmerican English
Number of pages11
StatePublished - 1998
EventNational Center for Photovoltaics Program Review Meeting - Denver, Colorado
Duration: 8 Sep 199811 Sep 1998


ConferenceNational Center for Photovoltaics Program Review Meeting
CityDenver, Colorado

NREL Publication Number

  • NREL/CP-590-25681


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