Development of contractor cells. Technical status report, Phase 1 report
The microgrooved passivated emitter solar cell approach combines a thin diffused top junction layer of approximately 0.2{mu}m depth and 120--180{Omega}/square sheet resistance with a tin (100--200A) silicon dioxide surface passivation layer. The front gridlines sit on top of a heavily diffused N++ region to reduce contact resistance between front gridlines and the N surface. High-quality float zone silicon with nominal resistivity of 0.20{Omega}-cm or 0.15 {Omega}-cm is used for this work. To achieve the highest possible concentration performance and lower system cost, the cell area was educed to 1 square centimeter from 1.58 square centimeters used at the University of new South Wales. The gridlines spacing is 127 microns designed to match the available prismatic cover. The baseline process requites four lithographic masking steps. A single lift-of process for evaporated gridlines is used to provide 8-microns-thick metallization to avoid the non-uniform metal plating and disposal of hazardous plating solutions. The front and back contact materials are space-qualified, vacuum-deposited layers of titanium-palladium and silver. A double-layer antireflection coating of TiO{sub x}and Al{sub 2}O{sub 3} is used to reduce surface reflection from the cells; this antireflection coating is designed to match with the SiO{sub 2} passivation layer. Four different gridlines widths (20, 16, 8, and 2 microns) we tested and evaluated for the best performance at high intensities. A three-level lithographic masking process was evaluated for reduced costs and a five-level lithographic masking process was evaluated for increased yield.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Applied Solar Energy Corp., City of Industry, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 10160090
- Report Number(s):
- SAND-92-7006; ON: DE92017343
- Resource Relation:
- Other Information: PBD: Jun 1992
- Country of Publication:
- United States
- Language:
- English
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