DocumentCode :
3513575
Title :
Analyzing emitter dopant inhomogeneities at textured Si surfaces by using 3D process and device simulations in combination with SEM imaging
Author :
Wagner, Hannes ; Steingrube, Silke ; Wolpensinger, Bettina ; Dastgheib-Shirazi, Amir ; Chen, Renyu ; Dunham, Scott T. ; Altermatt, Pietro P.
Author_Institution :
Dept. Solar Energy, Leibniz Univ. of Hannover, Hannover, Germany
fYear :
2012
fDate :
3-8 June 2012
Abstract :
The lowering of the phosphorus dopant density in the emitter of Si solar cells is a current topic in the photovoltaic industry. In lowly-doped emitters, diffusion inhomogeneities between the tops of the pyramids and the valleys affect the saturation current density J0. We quantify diffusion inhomogeneities by means of 3D process simulations, and we evaluate J0 by means of 3D device simulations. Finally, we compare the simulated diffusion results with a 2D dopant-contrast analysis obtained with a scanning electron microscope (SEM). Both methods show a deeper in-diffusion at the top of the pyramid and a shallower in-diffusion in the valley regions. Within the pyramidal faces, the diffusion is between both of these extreme points and comparable with in-diffusion at planar structures. The results of the device simulations indicate that the increase of J0 from planar to textured surfaces depends on the dopant profile and the surface passivation, but that a factor of about 5 is observed in our example, as is observed experimentally.
Keywords :
elemental semiconductors; phosphorus; scanning electron microscopy; silicon; solar cells; 2D dopant-contrast analysis; 3D device simulations; 3D process simulations; P; SEM imaging; Si; diffusion inhomogeneities; dopant density lowering; emitter dopant inhomogeneities; lowly-doped emitters; photovoltaic industry; saturation current density; scanning electron microscope; solar cells; surface passivation; textured surfaces; Doping profiles; Nonhomogeneous media; Semiconductor process modeling; Silicon; Solid modeling; Surface texture; Surface treatment; emitter dopant inhomogenities; saturation current density; simulations; textured surfaces;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Photovoltaic Specialists Conference (PVSC), 2012 38th IEEE
Conference_Location :
Austin, TX
ISSN :
0160-8371
Print_ISBN :
978-1-4673-0064-3
Type :
conf
DOI :
10.1109/PVSC.2012.6317625
Filename :
6317625
Link To Document :
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