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AssigneeEbara Solar, Inc.
InventorsDaniel L. Meier, Hubert P. Davis, Ruth A. Garcia, Joyce A. Jessup
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The present invention provides a system and method for creating self-doping contacts to silicon devices in which the contact metal is coated with a layer of dopant and subjected to high temperature, thereby alloying the silver with the silicon and simultaneously doping the silicon substrate and forming a low-resistance ohmic contact to it. A self-doping negative contact may be formed from unalloyed silver which may be applied to the silicon substrate by either sputtering, screen printing a paste or evaporation. The silver is coated with a layer of dopant. Once applied, the silver, substrate and dopant are heated to a temperature above the Ag—Si eutectic temperature (but below the melting point of silicon). The silver liquefies more than a eutectic proportion of the silicon substrate. The temperature is then decreased towards the eutectic temperature. As the temperature is decreased, the molten silicon reforms through liquid-phase epitaxy and while so doing dopant atoms are incorporated into the re-grown silicon lattice. Once the temperature drops below the silver-silicon eutectic temperature the silicon which has not already been reincorporated into the substrate through epitaxial re-growth forms a solid-phase alloy with the silver. This alloy of silver and silicon is the final contact material, and is composed of eutectic proportions of silicon and silver. Under eutectic proportions there is significantly more silver than silicon in the final contact material, thereby insuring good electrical conductivity of the final contact material.
A method of manufacturing a contact, comprising:
A method of manufacturing a semiconductor device, comprising:
A semiconductor device, comprising:
A method of manufacturing a contact, comprising:
A contact to a semiconductor having a semiconductor surface, formed by applying a silver layer to at least a portion of the surface, applying a dopant to at least a portion of the silver layer, heating the surface, silver layer and dopant until at least a portion of the silver layer, a portion of the dopant and a portion of the surface form a molten alloy, cooling the molten alloy until at least a portion of the dopant contained in the molten alloy is incorporated into an epitaxial re-growth region of at least a portion of the semiconductor, and the molten alloy forms into a substantially solid first region containing semiconductor atoms and dopant atoms, and a substantially solid second region containing silver atoms and dopant atoms, such that a solderable ohmic electrical contact is formed between at least a portion of the substantially solid second region and at least a portion of the epitaxial re-growth region.
A method of manufacturing a semiconductor device, comprising:
Dependencies are inferred from the claim text.