| 摘要 |
PURPOSE:To uniformly eliminate a high concentration doped layer on an N<+> layer surface with excellent reproducibility by a method wherein, after an N- type layer is formed on a P-type silicon substrate surface by impurity diffusion of group V element, a thermal oxide film is formed and eliminated by etching. CONSTITUTION:After a P<+> layer 2 is formed on a P-type single crystal silicon substrate, an N<+> layer 3 is formed by thermal diffusion of phosphorus. A wafer 1 treated in the above manner is subjected to thermal oxidation in an oxygen atmosphere at 850 deg.C or less, thereby forming a thermal oxide film of several 10's-120Angstrom in thickness on the whole surface of the wafer 1. The water 1 coated with the thermal oxide film 4 is dipped in etchant whose main component is hydrofluoric acid, and the thermal oxide film is once completely eliminated. At this time, the vicinity of the surfaces of the P<+> layer 2 and the N<+> layer 3 is also eliminated a little, and a P<+> layer 2-1 and an N<+> layer 3-1 are formed. After that, by performing anew thermal oxidation, the passivation film of a thermal oxide film 5 is formed and a solar battery cell is manufactured. |
