NOVELTY - Manufacturing solar cell unit comprises: (a) providing substrate comprising first and second surfaces; (b) performing heavy doping to first and second surfaces to form first doping region (110) and second doping region (120); (c) forming at least two first grooves and at least one second groove from first and second surfaces; (d) performing heavy doping to sidewalls of the first and second grooves to form a third doping region (130) and fourth doping region (140) and keeping surface doping type of the first and second doping regions unchanged to form a vertical solar cell array.    USE - The method is useful for manufacturing a solar cell unit.    ADVANTAGE - The method: reduces carrier combination at the surface area and is favorable for putting electrodes on side surfaces of the solar cell unit, thus improving light absorption efficiency and energy conversion efficiency; provides solar cell unit that has uniform doping type at its side surfaces, thus reduces difficulty experienced when processing side surfaces of solar cell unit; and forms a region analogous to a Zener diode, when a reverse bias is present, the structure allows flow of greater electrical current when the reverse voltage exceeds a certain value, to avoid reverse breakdown damage and when many solar cell units are operated in series, if any one of the solar cell units cannot work properly due to lack of solar radiation, the region analogous to a Zener diode structure (n+/p+ region) inside the solar cell units can guarantee that the entire serial circuit operates properly.    DETAILED DESCRIPTION - Manufacturing a solar cell unit comprises: (a) providing a substrate comprising a first surface and a second surface opposite to the first surface; (b) performing heavy doping to the first and second surfaces to form a first doping region (110) on the first surface and a second doping region (120) on the second surface; (c) forming at least two first grooves and at least one second groove from first and second surfaces, where each second groove located between two neighboring first grooves forms a vertical strip plate array comprising at least two strip plates and at least one sheet; and (d) performing heavy doping to sidewalls of the first and second grooves to form a third doping region (130) on the sidewall of the first groove and a fourth doping region (140) on the sidewall of the second groove and keeping the surface doping type of the first doping region and the second doping region unchanged to form a vertical solar cell array, where the type of impurities in the third doping region is contrary to the type of impurities in the fourth doping region the solar cell unit comprising a strip plate, which has a third surface and a fourth surface opposite to the third surface, where a third doping region and a fourth doping region are arranged on the third surface and fourth surface, a first doping region and a second doping region are arranged on side surfaces adjacent to the third surface and the fourth surface and the type of impurities in the third doping region is contrary to the type of impurities in the fourth doping region, and the surfaces of the first and second doping regions have uniform doping.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic cross-sectional view at each stage of forming the solar cell unit.    First doping region (110)    Second doping region (120)    Third doping region (130)    Fourth doping region (140)    First sheet (200)