Innovalight, Inc.

Eric Rosenfeld

Elena Rogojina

Maxim Kelman

Dmitry Poplavskyy

Giuseppe Scardera

Malcolm Abbott

A method of forming a floating junction on a substrate is disclosed. The method includes providing the substrate doped with boron atoms, the substrate comprising a front surface and a rear surface. The method also includes depositing a set of masking particles on the rear surface in a set of patterns; and heating the substrate in a baking ambient to a first temperature and for a first time period in order to create a particle masking layer. The method further includes exposing the substrate to a phosphorous deposition ambient at a second temperature and for a second time period, wherein a front surface PSG layer, a front surface phosphorous diffusion, a rear surface PSG layer, and a rear surface phosphorous diffusion are formed, and wherein a first phosphorous dopant surface concentration in the substrate proximate to the set of patterns is less than a second dopant surface concentration in the substrate not proximate to the set of patterns. The method also includes exposing the substrate to a set of etchants for a third time period, wherein the front surface PSG layer and the rear surface PSG layer are substantially removed; depositing a front surface SiNlayer and a rear surface SiNlayer; and forming a rear metal contact on the rear surface through the rear surface SiNlayer proximate to the set of patterns.

Methods of forming a floating junction on a solar cell with a particle masking layer

A method for selectively etching a silicon-containing film on a silicon substrate is disclosed. The method includes depositing a silicon-containing film on the silicon substrate. The method further includes baking the silicon-containing film to create a densified silicon-containing film, wherein the densified film has a first thickness. The method also includes exposing the silicon substrate to an aqueous solution comprising NHF and HF in a ratio of between about 6:1 and about 100:1, at a temperature of between about 20&#xb0; C. and about 50&#xb0; C., and for a time period of between about 30 seconds and about 5 minutes; wherein between about 55% and about 95% of the densified silicon-containing film is removed.

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Sunnyvale, CA, United States of America

Eric Rosenfeld