Electrical and Optical Characterisation of Gateless 22 nm FDSOI PIN-Diodes at 850 nm

We present electrical and optical (at a wavelength of 850 nm) measurement results of SOI PIN-diodes without a front-gate, with an intrinsic Si film thickness of only 6 nm. These PIN-diodes have been fabricated in a commercial Fully-Depleted Silicon-On-Insulator (FDSOI) technology, without requiring additional process steps. To the best of the author’s knowledge these are the first-ever published results of SOI PIN-diodes without a front-gate fabricated in a commercial FDSOI process. At -1 V reverse bias the measured responsivity is $35 \mu \mathrm{~A} / \mathrm{W}$, and the dark current density is $7.2 \mu \mathrm{~A} / \mathrm{cm}^{2}$. The -3 dB bandwidth is 5.9 GHz, and the -6 dB bandwidth is 15 GHz. Further, electrostatic back-gate tuning shows a significant effect on the electrical characteristics and optical responsivity. These PIN-diodes potentially open the way to new THz circuits, novel/complementary process control monitoring structures, and optical applications. They also enable interaction between the hybrid (bulk) and SOI devices, which is a unique feature of FDSOI technologies.