Effects of controllable process factors on Al rear surface bumps in Si solar cells
Effects of controllable process factors on Al rear surface bumps in Si solar cells
- 주제(키워드) Aluminum back surface field , Al bump , Solar cells , Al-Si eutectic alloy , Al-Si contact
- 발행기관 한국물리학회
- 발행년도 2012
- 총서유형 Journal
- UCI G704-001115.2012.12.1.006
- KCI ID ART001629042
- 본문언어 영어
초록/요약
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.
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