Quantum Efficiency Improvement of SOI p-i-n Lateral Diodes Operating as UV Detectors at High Temperatures

Thin-film lateral SOI p-i-n diodes can be used as photodetectors especially in the wavelength range of blue and ultra-violet (UV) radiation. Unlike vertical devices, lateral diodes can have depletion regions very close to the device surface, where the absorption of low-wavelengths radiation takes place. Due to this proximity to the surface, an MOS back-gate can control the charge density inside this region, allowing quantum efficiency improvement. This paper reports experimental results of SOI p-i-n photodetectors with different intrinsic lengths in the 300-500-K range, simultaneously considering back-gate bias and temperature influences. Indeed, the back-gate bias becomes very effective in terms of quantum efficiency control with up to 52.4% for LI = 1 mu m at T = 500 K in inversion mode, while in accumulation, the resulting efficiency was 48.2% at T = 500 K for the device with LI = 10 mu m at UV. These variations are related to the behavior of dark current and the recombination rate of the devices.