TY - JOUR
T1 - Effects of controllable process factors on Al rear surface bumps in Si solar cells
AU - Park, Sungeun
AU - Bae, Soohyun
AU - Kim, Hyunho
AU - Kim, Seongtak
AU - Kim, Young Do
AU - Park, Hyomin
AU - Kim, Soomin
AU - Tark, Sung Ju
AU - Son, Chang Sik
AU - Kim, Donghwan
N1 - Funding Information:
This work was supported by a Human Resources Development grant from the Korea Institute of Energy Technology Evaluation and Planning (KETEP) funded by the Ministry of Knowledge Economy , Republic of Korea ( No. 20104010100640 ), and this work was supported by the New & Renewable Energy of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No. 20093021010010 ).
PY - 2012/1
Y1 - 2012/1
N2 - High efficiency solar cells require good back surface field passivation and high back reflectance in the rear Al region. In module processes, wafer-based solar cell can break through stress during soldering uneven rear aluminum surfaces - a serious problem that affects throughput. This work examined rear surfaces with respect to controllable process factors such as ramping and cooling rates during rapid thermal processing, and the fineness of aluminum powder used in the screen-printed paste. A faster ramp up rate resulted in a uniform temperature gradient between the aluminum and silicon surfaces. As a results, the bumps on the aluminum surface were small and of high density. Fine aluminum metal powder in the paste for screen-printing contact points resulted in large distribution, high density bumps. Bumps formed during cooling in metallization, their sizes and densities were dependent the on uniformity of the aluminum and silicon liquid wetting of the silicon surface.
AB - High efficiency solar cells require good back surface field passivation and high back reflectance in the rear Al region. In module processes, wafer-based solar cell can break through stress during soldering uneven rear aluminum surfaces - a serious problem that affects throughput. This work examined rear surfaces with respect to controllable process factors such as ramping and cooling rates during rapid thermal processing, and the fineness of aluminum powder used in the screen-printed paste. A faster ramp up rate resulted in a uniform temperature gradient between the aluminum and silicon surfaces. As a results, the bumps on the aluminum surface were small and of high density. Fine aluminum metal powder in the paste for screen-printing contact points resulted in large distribution, high density bumps. Bumps formed during cooling in metallization, their sizes and densities were dependent the on uniformity of the aluminum and silicon liquid wetting of the silicon surface.
KW - Al bump
KW - Al-Si contact
KW - Al-Si eutectic alloy
KW - Aluminum back surface field
KW - Solar cells
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U2 - 10.1016/j.cap.2011.04.021
DO - 10.1016/j.cap.2011.04.021
M3 - Article
AN - SCOPUS:80054812324
VL - 12
SP - 17
EP - 22
JO - Current Applied Physics
JF - Current Applied Physics
SN - 1567-1739
IS - 1
ER -