Interaction of metal impurities with extended defects in crystalline silicon and its implications for gettering techniques used in photovoltaics

2009 ◽  
Vol 159-160 ◽  
pp. 264-268 ◽  
Author(s):  
M. Seibt ◽  
D. Abdelbarey ◽  
V. Kveder ◽  
C. Rudolf ◽  
P. Saring ◽  
...  
1995 ◽  
Vol 410 ◽  
Author(s):  
D. G. Keil ◽  
H. F. Calcote ◽  
R. J Gill

ABSTRACTSelf-propagating flames in pure silane-acetylene mixtures produce silicon carbide (SiC) powder and hydrogen as main products. Through precise control of the stoichiometry of the reactant gas mixture, it has been possible to produce white SiC at high yields. Characterization of such powders by TEM has shown that the nascent powder consists of polycrystalline hexagonal plates with a narrow size distribution (40 ± 7 nm diameter). Infrared spectroscopy of powders indicate microcrystalline SiC and little bound hydrogen. Chemical analysis by the ANSI method showed the powder to be >96 wt % SiC with an impurity of silica (3.9 weight %) due to air exposure of the powder. Traces (0.1 to 0.2 weight %) of both free carbon and free silicon were found. Metal impurities detected by SIMS were typically low: less than 10 ppba for aluminum, sodium, titanium and vanadium. Boron was observed at 10 ppma. Like the oxygen, the boron impurities are probably associated with exposure of the powders to the atmosphere.


2011 ◽  
Vol 178-179 ◽  
pp. 275-284 ◽  
Author(s):  
Michael Seibt ◽  
Philipp Saring ◽  
Philipp Hahne ◽  
Linda Stolze ◽  
M.A. Falkenberg ◽  
...  

This contribution summarizes recent efforts to apply transmission electron microscopy (TEM) techniques to recombination-active extended defects present in a low density. In order to locate individual defects, electron beam induced current (EBIC) is applied in situ in a focused ion beam (FIB) machine combined with a scanning electron microscope. Using this approach defect densities down to about 10cm-2 are accessible while a target accuracy of better than 50nm is achieved. First applications described here include metal impurity related defects in multicrystalline silicon, recombination and charge collection at NiSi2 platelets, internal gettering of copper by NiSi2 precipitates and site-determination of copper atoms in NiSi2.


Author(s):  
Bijaya Paudyal ◽  
Yo Han Yoon ◽  
David Cornwell ◽  
Phil Shaw ◽  
Francisco Machuca

2016 ◽  
Vol 255 ◽  
pp. 344-347 ◽  
Author(s):  
Michael Haslinger ◽  
M. Soha ◽  
S. Robert ◽  
M. Claes ◽  
Paul W. Mertens ◽  
...  

Advanced concepts for photovoltaic silicon solar cells, especially high-efficiency n-type solar cells, requires appropriate wet cleaning treatment in order to remove metallic contamination prior to high temperature processes like diffusion and passivation [1]. The cost of the cleaning process should be as low as possible that requires an optimized usage of the chemicals by increasing process tank lifetimes and developing dedicated feed and bleed recipes. The just clean enough concept has been developed to fulfil the needs of PV industry to minimize the consumption of chemicals. When the dominant contamination metal is identified in quality and quantity, a dedicated wet chemical cleaning process can be applied to remove the metal concentration from the semiconductor surface under a specified limit with the minimum volume on cleaning solution. The paper describes how to optimize a dedicated wet cleaning process for prominent metal impurities like Fe, Cu, Cr, Ti, Co and Zn. For each metal an exchange volume is determined to develop a feed and bleed recipe. The accumulation of the metal impurities in the process tank is calculated and process tank lifetimes are predicted.


2009 ◽  
Vol 6 (8) ◽  
pp. 1847-1855 ◽  
Author(s):  
M. Seibt ◽  
D. Abdelbarey ◽  
V. Kveder ◽  
C. Rudolf ◽  
P. Saring ◽  
...  

1995 ◽  
Vol 386 ◽  
Author(s):  
M. Konuma ◽  
I. Silier ◽  
A. Gutjahr ◽  
E. Bauser ◽  
F. Banhart ◽  
...  

ABSTRACTBy liquid phase epitaxy (LPE) we have grown silicon layers on silicon and partially masked silicon at temperatures below 450 °C from Ga and Ga-In solutions. Oxidation of the cleaned silicon substrate surfaces before epitaxial growth has been prevented by a buffered hydrofluoric acid treatment. The epitaxial layers reached a thickness of 7 jim and were free of extended defects.Low growth temperatures make it possible to grow silicon layers also on pre-treated glass substrates. The amorphous glass is first coated with a thin nano-crystalline silicon layer which is deposited by plasma processes from a mixture of SiH4/H2 gas. The grains in the silicon layers grown from Ga solution on glass have reached sizes up to 100 μm.


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