Damage to solid-state photodiodes by vacuum ultraviolet radiation

We report experimental results on the stability of photodiodes obtained at three different wavelengths in the vacuum ultraviolet spectral region. Two of these experiments were based on radiation damage inflicted with excimer lasers at 193 and 157 nm and one of them used 135 nm synchrotron radiation. It was found that the detector degradation rate increased considerably with the photon energy and depended on the structure of the photodiodes. Detectors based on the Si/SiO 2 interface were damaged much faster than Schottky-type diodes or Si diodes with metal passivating layers. Possible damage mechanisms to the Si/SiO 2 interface and its electronic structure are reviewed. In the end, a model to quantify the dependence of the damage on the photon energy is introduced.