TY - JOUR

T1 - Defect imaging in multicrystalline silicon using a lock-in infrared camera technique

AU - Pohl, Peter

AU - Schmidt, Jan

AU - Schmiga, Christian

AU - Brendel, Rolf

N1 - Funding Information: Funding was provided by the State of Lower Saxony and the German Federal Ministry for the Environment, Nature Conservation, and Nuclear Safety (BMU). The authors are grateful to N. Enjalbert of Photowatt International S.A.S (France) for supplying mc-Si wafers. The authors gratefully acknowledge fruitful discussions with K. Bothe, B. Fischer, and N. P. Harder. ISFH is a member of the German Forschungsverbund Sonnenenergie.

PY - 2007

Y1 - 2007

N2 - We image the lifetime distribution of multicrystalline silicon wafers by means of calibrated measurements of the free-carrier emission using an infrared camera. The spatially resolved lifetime measurements are performed as a function of the light-generated excess carrier density, showing a pronounced increase in lifetime with decreasing injection density at very low injection levels. Two theoretical models are applied to describe the abnormal lifetime increase: (i) minority-carrier trapping and (ii) depletion region modulation around charged bulk defects. The trapping model is found to give better agreement with the experimental data. By fitting the trapping model to each point of the lifetime image recorded at different injection levels, we generate a trap density mapping. On multicrystalline silicon wafers we find a clear correlation between trap and dislocation densitymappings.

AB - We image the lifetime distribution of multicrystalline silicon wafers by means of calibrated measurements of the free-carrier emission using an infrared camera. The spatially resolved lifetime measurements are performed as a function of the light-generated excess carrier density, showing a pronounced increase in lifetime with decreasing injection density at very low injection levels. Two theoretical models are applied to describe the abnormal lifetime increase: (i) minority-carrier trapping and (ii) depletion region modulation around charged bulk defects. The trapping model is found to give better agreement with the experimental data. By fitting the trapping model to each point of the lifetime image recorded at different injection levels, we generate a trap density mapping. On multicrystalline silicon wafers we find a clear correlation between trap and dislocation densitymappings.

UR - http://www.scopus.com/inward/record.url?scp=34247269162&partnerID=8YFLogxK

U2 - 10.1063/1.2713933

DO - 10.1063/1.2713933

M3 - Article

AN - SCOPUS:34247269162

VL - 101

JO - Journal of applied physics

JF - Journal of applied physics

SN - 0021-8979

IS - 7

M1 - 073701

ER -