Investigating subsurface damages in semiconductor–insulator–semiconductor solar cells with THz spectroscopy

The influence of near‐surface crystal damage on carrier dynamics in silicon has been investigated with optical‐pump THz‐probe and THz emission studies. The surface damage is caused by a plasma process used for the fabrication of the ultrathin insulator within semiconductor–insulator–semiconductor (SIS) solar cells. The ion bombardment during the plasma process introduces a highly damaged subsurface region. Furthermore, the integration of positive interface charges leads to the formation of a depletion region that can be detected via the emitted THz radiation. The results are compared with classic I – U ‐characterization demonstrating that THz spectroscopy can be used as a supplementary tool for the investigation of process‐induced surface damages.