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Device location: F&E4-SOLAR LAB

Lab location: Building 310 Room no. 203

Phone number:

Lab leader: Ulrich Wilhelm Paetzold

Principal users: Ulrich Wilhelm Paetzold, Wensheng Yan.

Access: Only trained and authorized users may use the setup. Contents [hide]

Short Description

WCT-120 instruments showcase our unique measurement and analysis techniques, including the highly regarded Quasi-Steady-State Photoconductance (QSSPC) lifetime measurement method developed by Sinton Instruments in 1994. The QSSPC technique is ideal for monitoring multicrystalline wafers, dopant diffusions, and low-lifetime samples. This method complements the use of the transient photoconductance technique that is also standard on this instrument.The QSSPC lifetime measurement also yields the implied open-circuit voltage (versus illumination) curve, which is comparable to an I-V curve at each stage of a solar cell process. WCT System Capabilities: Primary application: Step-by-step monitoring and optimization of a fabrication process. Other applications: • Monitoring initial material quality • Detecting heavy metals contamination during wafer processing • Evaluating surface passivation and emitter dopant diffusion • Evaluating process-induced shunting using the implied I-V measurement Datei:product-photo-WCT-120-main-WM-v2.jpg

Start-up Procedure

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Standard Operating Procedure: Assembly Equipments Stages : WCT-120 & Suns-Voc Flash Lamp Assembly Bulb & Reflector Power Supply Flash Lamp Trigger Flash Lamp Tower Filters Neutral Density Filters IR Pass Filter Visible Pass blue filter Adjustable height Stand Data Acquisition System Connector Box BNC Cables , thermocouple & other Probes PCI Card connection with Computer

Precautions: 1.Do NOT touch the filters or the filter tray which has glass diffuser glued into it, with bare hands. Use gloves or tissue paper for the same. 2.Make sure that the filter tray/flash mount assembly does NOT fall down while sliding it over the flash tower for adjusting height of the flash. 3.Ensure that the BNC cable and flash trigger connections are in place based on the measurement to be done i.e. to lifetime tester stage or Suns VOC stage. 4.Note down the height of the flash from the stage, the setting on the flash (1/1 or 1/64) and the filter being used during measurement. Different users tend to change this according to their requirements. 5.Make sure that the reference cell is NOT covered during the measurement. 6.Do NOT start the measurement on Lifetime tester until it is thermally stabilized i.e. Red LED is OFF. 7.During chemical passivation, ensure that solution does NOT spill on the stage. 8.For Suns VOC measurement, ensure that sample consists of P-N junction and both P N sides can be probed properly. 9.Ensure that proper action is taken for addressing error messages in the measurement:i.Saturated reference cell: Height of the flash is adjusted to change the intensity of light to avoid saturation of reference cell.ii.Min MCD < Specified MCD < Max MCD: Change the specified minority carrier density to fit in the measured range of minority carrier density.iii.Remove the sample on lifetime tester stage during zeroing of the instrument: No sample in the vicinity of stage during zeroing of the instrument. 10.Ensure that SUMMARY file is NOT cut pasted during the data transfer: