Method for Producing a Back Contact System for a Silicon Thin-Film Solar Cell

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This patent describes a manufacturing method for creating a high-precision, reliable rear-side contact system (ALPS: All-by-Laser Point-Contact Scheme) for silicon thin-film solar cells. The process involves using laser marking and selective chemical etching to form precise holes in layered materials, enabling the connection of metal contacts without damaging the sensitive emitter layer. The technique ensures fine positional accuracy, scalability for industrial production, and protects key layers from laser-induced damage.

Use CasesContent extracted from patent full text and abstract with AI.

• Mass production of silicon thin-film solar cells with improved efficiency and reliability.
• Manufacturing thin-film photovoltaic modules for solar farms or building-integrated photovoltaics (BIPV).
• Production of next-generation heterojunction solar cells requiring sensitive emitter protection.
• Development of advanced solar panels for portable or consumer electronics.
• Adaptation for use in other semiconductor device fabrication where precise, layered contact structures are required.

BenefitsContent extracted from patent full text and abstract with AI.

• Enables high-precision contact formation, improving solar cell efficiency and reliability.
• Scalable for large-scale industrial production due to the elimination of complex lithography and masking steps.
• Reduces potential damage to sensitive layers, especially in heterojunction solar cells, enhancing device lifetime and performance.
• Allows for full laser-based structuring processes, increasing automation and simplifying alignment.
• Accommodates a wide range of silicon layer types and thicknesses, offering flexibility in cell design.
• Potentially lowers production costs and increases throughput by streamlining multiple process steps.

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Patent Abstract

In the method according to the invention, which makes it possible to produce a rear-side "AII-by-laser point-contact scheme" (ALPS) contact system, a TCO layer is applied before the application of the organic insulating layer to the emitter layer, after that holes for the contacts with respect to the silicon absorber layer are made in the insulating layer, in that firstly markings are produced at future locations of the contacts with respect to the silicon absorber layer in the organic insulating layer with a pulsed UV laser without material being removed all the way through, and these markings are subsequently etched in at least one wet-chemical, selective etching step, initially as far as the TCO layer and then in at least one further etching step through the emitter layer to the silicon absorber layer, subsequently holes for the contacts with respect to the emitter layer are made in an analogous way in the insulating layer, wherein the sensitive emitter is not damaged. Subsequently, because of the exclusive use of lasers for the positioning-relevant processes, the holes made for the contacts with respect to the Si absorber layer are selectively doped by means of a laser.