NOVELTY - The method comprises forming a dielectric layer (125) over a part of a rear surface of a silicon solar cell, depositing a metal layer over the dielectric layer, anodizing the metal layer to form a porous layer, depositing a material layer within pores of the porous layer and over a surface of the porous layer, and forming metal electrodes to contact semiconductor regions of the silicon solar cell. The dielectric layer covers the part of the rear surface of the silicon solar cell. The metal layer covers a part of the dielectric layer.    USE - The method is useful for forming a dielectric structure for a rear surface of a silicon solar cell.    ADVANTAGE - The method ensures economic, efficient and simple formation of the dielectric structure with high throughput and reduced material consumption thus increasing lifetime and improving energy conversion efficiencies and surface passivation of the silicon solar cell.    DETAILED DESCRIPTION - The method comprises forming a dielectric layer (125) over a part of a rear surface of a silicon solar cell, depositing a metal layer over the dielectric layer, anodizing the metal layer to form a porous layer, depositing a material layer within pores of the porous layer and over a surface of the porous layer, and forming metal electrodes to contact semiconductor regions of the silicon solar cell. The dielectric layer covers the part of the rear surface of the silicon solar cell. The metal layer covers a part of the dielectric layer. The material layer deposited over the surface of the porous layer comprises: a dye, reflective particles or light scattering nanoparticles and a source of dopant; and the metal layer that is deposited over the porous layer and within the pores of the porous layer without contacting the rear surface of the silicon solar cell. The material layer deposited over the surface of the porous layer: seals the pores of the porous layer to trap air in the pores of the porous layer; and comprises a polymer encapsulant into which the dye, reflective particles or light scattering nanoparticles are loaded. The polymer encapsulant is applied over the porous material and into the pores of the porous material. The porous layer is locally melted at some points in which the porous layer contacts underlying silicon, where the porous layer and underlying dielectric layer are disrupted and the underlying silicon is exposed and doped with aluminum. The melting of the porous layer causes the underlying silicon to absorb the dopant. The disruption and doping are performed with a laser. The metal deposited over the surface of the porous layer forms a metal contact layer, which contacts the doped silicon via the disruption in the porous layer and underlying dielectric layer. The metal contact layer: is formed to contact a base of a front-junction solar cell, a base of a rear-junction solar cell and a rear emitter of a rear-junction solar cell; and contacts two semiconductor regions of two different semiconductor polarities of the solar cell. The step of forming metal electrodes comprises depositing a polymer layer on the rear surface of the solar cell in a pattern corresponding to a desired metal isolation pattern, depositing a conductive metal contact layer, by sputtering or thermal evaporation, over the rear surface to contact the semiconductor regions of the solar cell, and processing the polymer layer to disrupt the conductive metal contact layer in the pattern of the polymer layer to isolate metal of the conductive metal contact layer that contacts different semiconductor regions. The processing step involves subjecting the silicon solar cell to ultrasonic excitation within a liquid comprising a solvent and water (10%), and heating the silicon solar cell to soften or melt the polymer layer. The polymer layer is soluble in an organic solvent and water, and is applied by an inkjet printing device or an aerosol jet printing device. The silicon solar cell comprises a semiconductor substrate having a thickness of less than 150-160 mu m. INDEPENDENT CLAIMS are included for:    (1) a silicon solar cell;    (2) a method of forming an electrical contact for a solar cell device; and    (3) a method of forming an anodized metal oxide layer on a surface of a semiconductor device.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a rear contact cell design.    P-type wafer (110)    Front surface (115)    Dielectric layer (125)    Thin silicon dioxide layer (126)    Isolation openings. (160)