BACK CONTACT SOLAR CELLS USING ALUMINUM-BASED ALLOY METALLIZATION
First Claim
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1. A back contact solar cell structure, comprising:
- a first aluminum-silicon alloy layer on a backside surface of a semiconductor solar cell substrate, said first aluminum-silicon alloy layer comprising base electrodes and emitter electrodes connected to base regions and emitter regions on said semiconductor solar cell substrate;
an electrically insulating backplane layer on said first aluminum-silicon alloy, said backplane layer comprising via holes to access said first aluminum silicon alloy layer, said via holes drilled through said backplane layer and stopped at said first aluminum-silicon alloy layer at selective positions without punching through said first aluminum-silicon alloy layer, to form base contacts and emitter contacts to said first metal layer; and
a second metal layer of electrically conductive metal on said electrically insulating backplane layer, said second metal layer electrically contacted to said first aluminum silicon alloy layer through said via holes.
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Abstract
Methods and structures for photovoltaic back contact solar cells having multi-level metallization with at least one aluminum-silicon alloy metallization layer are provided.
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Citations
22 Claims
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1. A back contact solar cell structure, comprising:
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a first aluminum-silicon alloy layer on a backside surface of a semiconductor solar cell substrate, said first aluminum-silicon alloy layer comprising base electrodes and emitter electrodes connected to base regions and emitter regions on said semiconductor solar cell substrate; an electrically insulating backplane layer on said first aluminum-silicon alloy, said backplane layer comprising via holes to access said first aluminum silicon alloy layer, said via holes drilled through said backplane layer and stopped at said first aluminum-silicon alloy layer at selective positions without punching through said first aluminum-silicon alloy layer, to form base contacts and emitter contacts to said first metal layer; and a second metal layer of electrically conductive metal on said electrically insulating backplane layer, said second metal layer electrically contacted to said first aluminum silicon alloy layer through said via holes.
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2. An interdigitated back-contact solar cell structure, comprising:
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a crystalline semiconductor absorber layer comprising; a surface passivation and antireflection coating layer on the frontside of said semiconductor absorber; a thicker lightly doped n-type base layer and a thinner heavily doped p-type emitter junction on the backside of said semiconductor absorber; and a backside structure, said backside structure comprising; a patterned backside dielectric dopant source and surface passivation structure with base and emitter contact openings; a first interdigitated base and emitter metallization layer comprising a plurality of direct-write printed silicon-containing aluminum fingers directly on said patterned backside dielectric dopant source and passivation structure and contacting said base and emitter regions through said base and emitter contact openings; an electrically insulating backplane layer attached to said solar cell structure on said patterned backside dielectric dopant source and surface passivation structure and said first patterned interdigitated base and emitter metallization layer, said backplane layer comprising a plurality of via holes landing on said first interdigitated base and emitter metallization layer; and a second interdigitated base and emitter metallization layer formed on said electrically insulating backplane layer, said second interdigitated base and emitter metallization layer comprising patterned conductor fingers aligned substantially orthogonal to said first interdigitated base and emitter metallization layer. - View Dependent Claims (3, 4, 5, 6, 7, 8)
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9. A method for forming an interdigitated back-contact solar cell structure on a crystalline semiconductor absorber layer, comprising:
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forming a passivation and antireflection coating layer on the frontside of a semiconductor absorber; forming a thicker lightly doped n-type base layer and a thinner heavily doped p-type emitter junction on the backside of said semiconductor absorber; and forming a backside structure on said thicker lightly doped n-type base layer and said thinner heavily doped p-type emitter junction on the backside of said semiconductor absorber, comprising; forming a patterned backside dielectric dopant source and passivation structure with base and emitter contact openings; forming a first interdigitated base and emitter metallization layer comprising a plurality of direct-write printed silicon-containing aluminum fingers directly on said patterned backside dielectric dopant source and passivation structure and contacting said base and emitter regions through said base and emitter contact openings; forming an electrically insulating backplane layer attached to said solar cell structure on said patterned backside dielectric dopant source and passivation structure and said first patterned interdigitated base and emitter metallization layer, said backplane layer comprising a plurality of via holes landing on said first interdigitated base and emitter metallization layer; and forming a second interdigitated base and emitter metallization layer on said electrically insulating backplane layer, said second interdigitated base and emitter metallization layer comprising patterned conductor fingers aligned substantially orthogonal to said first interdigitated base and emitter metallization layer. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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- 19. A silicon-containing aluminum alloy for forming an interdigitated back-contact base and emitter contact metallization structure comprising aluminum-silicon alloy particles shaped substantially as a mixture of flake-shaped particles and spherical-shaped particles.
Specification