The structural, electronic, and optical properties of the so‐called local defect layer (LDL), the key feature of the junction near the local defect layer (JNLD) Si solar cell, have been studied after each processing step using transmission electron microscopy, spreading resistance (SR), and absorption measurements. Our results show that a layer of 20–80 nm sized bubbles is formed beneath the Si surface after proton implantation and a two‐step annealing process. The SR profiles reveal that the implantation‐damaged Si material is almost electronically reconstituted after the second annealing step. This LDL absorbs less than 2% of the sunlight; therefore, the efficiency of a JNLD solar cell cannot be increased by more than 2% (relative) compared to an unimplanted reference cell. However, by using higher implantation doses a buried textured layer is formed which leads to an enhanced absorption and has a similar beneficial effect in solar cells as a textured surface. © 1995 American Institute of Physics.