Patent ID: 9076657
Filing Date: 2015-07-07
Classification: C25D,C25F,H01L,Y02E,Y02P

Abstract:
1. A method comprising: a) providing a semiconductor wafer comprising a front side comprising an emitter layer comprising oxidized sections, a back side and a PN junction; b) contacting the semiconductor wafer with a composition consisting of alkali metal bifluorides, sulfamic acid and water; c) generating a current in the composition; d) applying anodic current for a predetermined time, followed by turning the anodic current off for a predetermined time and repeating the cycle to form a nanoporous layer on the oxidized sections of the emitter layer of the semiconductor wafer, wherein a sheet resistivity of the emitter layer is increased by 5% to 40% of the sheet resistivity of the emitter layer prior to application of the anodic current; e) contacting the semiconductor wafer with a metal plating solution; and f) generating an electrical current in the metal plating solution to deposit metal on the nanoporous emitter layer.