Mobil Solar Energy Corporation

Zinovy Y Vayman

Jack I Hanoka

James A Gregory

A method of forming a metallization pattern on a substrate used in the fabrication of a solar cell or other semiconductor device. The metallization pattern is formed by (1) hydrogen passivating a silicon substrate having a P/N junction formed therein adjacent one surface of the substrate, with a damaged surface layer being formed in conjunction with the hydrogen passivation process, and (2) laser annealing selected portions of said damaged layer whereby said selected portions form a metallization pattern to which selected metals will securely adhere when applied by immersion plating. The foregoing fabrication steps may be performed simultaneously. A layer of material comprising SiO.sub.x may be redeposited on the one surface of the substrate as part of the hydrogen passivation procedure. In the laser annealing step, sections of the redeposited material scanned by the laser beam are ablated and the exposed underlying damaged surface layer is annealed.

Method of fabricating solar cells

A method of bulk passivating a crystalline or polycrystalline substrate made from silicon, germanium, gallium arsenide or other III-V compounds, and II-VI compounds by exposing the substrate to a fluorine ion beam created by a Kaufman ion source. The Kaufman ion source is controlled so that the intensity of and duration of exposure to the fluorine ion beam is sufficient to bulk passivate the substrate. Preferably, the substrate is preheated to a selected temperature prior to the ion beam exposure.

Method of passivating crystalline substrates

An improved optical match to a subsequently-formed antireflection overcoating is achieved by providing a silicon solar cell substrate with an altered surface layer that is formed by an ion-beam process, and has a refractive index between about 3.4 and about 3.6 at 633 nm and between about 3.6 and about 3.8 at 442 nm. The surface layer is formed by adding between about 2% and about 10% methane, by volume, to the hydrogen flow in a Kaufman type broad beam ion source.

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Brookline, MA, United States of America

Zinovy Y Vayman