Optical Absorption Study of the Interaction between Group II Acceptors and Hydrogen in Si

Abstract

The interaction between hydrogen (H) and Zn was studied from the measurements of optical absorption spectra of H and Zn-doped Si crystals. FZ Si crystals were doped with Zn by annealing the crystals in Zn vapor at 1200 °C followed by quenching. After Zn-doping, the specimens were doped with H and/or deuterium (D) by annealing them in a H and/or D ambient followed by quenching. Optical absorption spectra of the above specimens were measured at about 6 K with an FT-IR spectrometer. Hydrogen atoms are known to passivate Zn acceptors partially since the optical absorption intensity associated with electronic transitions becomes much weaker after hydrogenation. Instead, other absorption peaks appear at around 2130 cm−1. From the comparison of separations of those peaks, they are identified to be due to electronic transitions associated with Zn–H acceptors. Optical absorption peaks associated with Zn–D acceptors have higher energies by about 12.1 cm−1 than those of Zn–H acceptors.