NOVELTY - A solar cell (500) includes base diffusion regions (503) for collecting charge carriers in the solar cell, two metal contacts, and a first insulator layer. The base diffusion regions are surrounded by a continuous emitter diffusion region (502) on a back side of the solar cell. The continuous emitter diffusion region is configured to collect minority charge carriers in the solar cell.    USE - Solar cell for concentrator systems.    ADVANTAGE - The solar cell has higher efficiency than conventional solar cells.    DETAILED DESCRIPTION - A solar cell (500) comprises base diffusion regions (503) for collecting charge carriers in the solar cell, two metal contacts, and a first insulator layer. The base diffusion regions are surrounded by a continuous emitter diffusion region (502) on a back side of the solar cell. The continuous emitter diffusion region is configured to collect minority charge carriers in the solar cell. The first metal contact is electrically coupled to the continuous emitter diffusion region. The second metal contact is electrically coupled to a base diffusion region in the base diffusion regions. The first insulator layer is provided between the second metal contact and the continuous emitter diffusion region. The first insulator layer electrically insulates the continuous emitter diffusion region from the second metal contact. The second metal contact is electrically coupled to the base diffusion region by way of a contact hole through the first insulator layer. An INDEPENDENT CLAIM is included for fabrication of solar cell comprising:    (A) forming a first doped layer over a first surface of a substrate;    (B) forming a second doped layer over the first surface of the substrate;    (C) diffusing a first dopant from the first doped layer to form base diffusion regions for collecting majority charge carriers on a back side of the solar cell, where the base diffusion regions can collect majority charge carriers in the solar cell;    (D) diffusing a second dopant from the second doped layer to form a continuous emitter diffusion region surrounding the base diffusion regions on the back side of the solar cell, where the emitter diffusion region can collect minority charge carriers in the solar cell;    (E) forming a first metal grid (505) on the back side of the solar cell, where the first metal grid is electrically coupled to a base diffusion region in the base diffusion regions; and    (F) forming a second metal grid (506) on the back side of the solar cell, where the second metal grid is electrically coupled to the continuous emitter diffusion region.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a solar cell.    Solar cell (500)    Silicon wafer (501)    Emitter diffusion region (502)    Base diffusion regions (503)    Metal grids (505, 506)