scholarly journals Effect of Cooling Rate During Thermal Processes on the Electrical Properties of Cast Multi-Crystalline Silicon

2021 ◽  
Author(s):  
Panbing Zhou ◽  
Shilong Liu ◽  
Naigen Zhou ◽  
Xiuqin Wei ◽  
Lang Zhou
Keyword(s):  
Grain Boundaries ◽  
Cooling Rate ◽  
Carrier Lifetime ◽  
Minority Carrier ◽  
Crystalline Silicon ◽  
Imaging Techniques ◽  
Minority Carrier Lifetime ◽  
Test System ◽  
Structural Defects ◽  
Lifetime Test

Abstract Photoluminescence（PL）imaging techniques and the minority carrier lifetime test system were employed to investigate the variation of the interstitial iron (Fei) concentration, the recombination activity of structural defects and the minority carrier lifetime of cast multicrystalline silicon (mc-Si) in response to the cooling rate after heating. The results showed that when the mc-Si wafers are heated to high-temperature (1000 °C) and then cooled to ambient temperature with different cooling rate, the Fei concentration, the number of recombination active dislocations and grain boundaries increased as the cooling rate rises while the minority carrier lifetime decreased. If cast mc-Si is heated followed by faster cooling at 30 °C/s, the Fei concentration increase by 223% and the electrical activity of grain boundaries, dislocations and intragrain increase significantly, that is to say, the whole wafer is heavily contaminated with metal impurities, and present extremely low minority carrier lifetime.

Minority carrier lifetime scan map in crystalline silicon wafers

1999 ◽  
Vol 70 (10) ◽  
pp. 4044-4046 ◽  
Author(s):  
J. Gervais ◽  
O. Palais ◽  
L. Clerc ◽  
S. Martinuzzi
Keyword(s):  
Carrier Lifetime ◽  
Minority Carrier ◽  
Crystalline Silicon ◽  
Minority Carrier Lifetime ◽  
Silicon Wafers

Minority Carrier Lifetime Improvement of Multicrystalline Silicon Using Combined Saw Damage Gettering and Emitter Formation

2015 ◽  
Vol 242 ◽  
pp. 126-132 ◽  
Author(s):  
George Martins ◽  
Ruy S. Bonilla ◽  
Toby Burton ◽  
P. MacDonald ◽  
Peter R. Wilshaw
Keyword(s):  
Carrier Lifetime ◽  
Minority Carrier ◽  
Crystalline Silicon ◽  
Minority Carrier Lifetime ◽  
High Concentration ◽  
Production Methods ◽  
Cell Efficiency ◽  
Annealing Conditions ◽  
Maximum Lifetime ◽  
Current Production

In this work we use Saw Damage Gettering (SDG) in combination with emitter formation to improve the minority carrier lifetime of highly contaminated multi-crystalline silicon wafers. This process is applied to wafers from the bottom of ingots, commonly referred to as the “red zone”, which are currently discarded since their high concentration of impurities limits the efficiency of solar cells produced therefrom. SDG is a potentially simple technique designed to upgrade these wafers. In this technique, bulk impurities are dissolved via annealing. The wafers are then cooled which generates a super-saturation of impurities in solution. The system then relaxes through the formation of precipitates in the saw damaged region. SDG is shown to be enhanced when using a temperature dependent cooling rate which maximizes the flux of impurities to the saw damaged regions. In addition, these benefits were observed even after an additional gettering process occurring during an emitter formation procedure. The SDG annealing conditions required to achieve the maximum lifetime were altered by the introduction of the emitter formation process. The enhancement generated by the SDG process may be sufficient to enable red-zone wafers to be processed is the same manner as higher quality no-red zone wafer wafers without adversely affecting the resultant cell efficiency. Due to its simplicity, it is expected that SDG can easily be incorporated into current production methods.

Minority Carrier Lifetime Behavior in Crystalline Silicon in Rapid Laser Heating

2012 ◽  
Vol 51 ◽  
pp. 03CA04
Author(s):  
Toshiyuki Sameshima ◽  
Koichi Betsuin ◽  
Tomohisa Mizuno ◽  
Naoki Sano
Keyword(s):  
Laser Heating ◽  
Carrier Lifetime ◽  
Minority Carrier ◽  
Crystalline Silicon ◽  
Minority Carrier Lifetime

Isothermal Treatment Effects on the Carbon Vacancy in 4H Silicon Carbide

2015 ◽  
Vol 821-823 ◽  
pp. 351-354 ◽  
Author(s):  
Hussein M. Ayedh ◽  
Roberta Nipoti ◽  
Anders Hallén ◽  
Bengt Gunnar Svensson
Keyword(s):  
Cooling Rate ◽  
Carrier Lifetime ◽  
Minority Carrier ◽  
Minority Carrier Lifetime ◽  
Temperature Treatment ◽  
The Other ◽  
High Temperature Treatment ◽  
Isothermal Treatment ◽  
Equilibrium Conditions ◽  
Carbon Vacancy

The carbon vacancy (VC) is a minority carrier lifetime controlling defect in 4H-SiC and it is formed during high temperature treatment. In this study, we have performed heat treatment on two sets of n-type 4H-SiC epitaxial samples. The first set was isothermally treated at 1850 °C to follow the evolution of VCas a function of time. The VCconcentration is not affected by changing the duration. Samples of the other set were treated at 1950 °C for 10 min, but with different cooling rates and a reduction of the VCconcentration was indeed demonstrated by lowering the cooling rate. The VCconcentration in the slow-cooled sample is about 2 times less than in the fast-cooled one, reflecting a competition between equilibrium conditions and the cooling rate.

scholarly journals Investigation on the Impact of Metallic Surface Contaminations on Minority Carrier Lifetime of a-Si:H Passivated Crystalline Silicon

2011 ◽  
Vol 8 ◽  
pp. 288-293 ◽  
Author(s):  
Florian Sevenig ◽  
Lena Breitenstein ◽  
Antje Oltersdorf ◽  
Karin Zimmermann ◽  
Martin Hermle
Keyword(s):  
Carrier Lifetime ◽  
Minority Carrier ◽  
Crystalline Silicon ◽  
Minority Carrier Lifetime ◽  
Metallic Surface ◽  
The Impact
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