Defect generation/passivation by low energy hydrogen implant for silicon solar cells

Low-energy ion implant in silicon is shown to produce defects including surface damage, hydrogen agglomeration, formation of platelets with (111) habit plane, and decoration of dislocations. Hydrogen also produces an inversion type of surface on boron-doped silicon. These effects indicate that a preferred approach for passivation is to incorporate hydrogen from the back side of the cell. A backside H⁺ implant technique is described. The results show that the degree of passivation differs for various devices. A comparison of the defect structures of hydrogenated devices indicates that the structure and the distribution of defects in the bulk of the material plays a significant role in determining the degree of passivation