Persistent photoconductivity in SIMOX films

Photoinduced transient spectroscopy (PITS) was used to measure the persistent photoconductive (PPC) response in film resistors fabricated on two different commercial n-type SIMOX (separation by implantation of oxygen) wafers. A broadband, single-shot, flashlamp-pumped dye-laser pulse was used to photoexcite interband electrons in the film, and the decay of the induced excess carrier population was measured at temperatures in the 60-220 K range. The post-illumination conductivity transients observed show PPC signals exhibiting a nonexponential character. They were recorded for periods of time up to 30 s at constant temperature. Presented are the excess conductivity in SIMOX film annealed in nitrogen at 1300°C for 6 h and the hole-trap volume density at the conductive-film-buried-silicon interface