Silicon-on-Insulator Photodiode on Micro-Hotplate Platform With Improved Responsivity and High-Temperature Application

This paper reports on the performance of a silicon-on-insulator photodiode suspended on a dielectric membrane. The micro-hotplate platform consists of a micro-heater and a thin-film lateral P
⁺
/P
^-
/N
⁺
(PIN) photodiode. Without optimizing the multilayer stack on top of the PIN diode, experimental responsivities of the suspended photodiodes at room temperature (RT) are 0.02-0.06/W within the visible and near the IR light range, under a reverse bias of -2 V. Up to 2.5×, responsivity improvement has been achieved with regard to the diodes on the substrate thanks to reflection from the gold finish layer of the device package acting as a bottom mirror. Optimizing the layer stack above the diode, the responsivity of the on-membrane device can be theoretically improved up to 0.09-0.11 A/W within 450-520-nm wavelength range. Measured from RT up to 200 °C, the photodiodes on membrane continuously show an improved optical response under high-power LED illumination. Assisted by the micro-heater as heat source, the suspended photodiode can work stably up to 200 °C with in situ temperature sensing and control, which makes it highly suitable and attractive for high-temperature application. Full 2-D ATLAS device simulations have been comprehensively performed to investigate the optical and electrical characteristics. Very good agreement has been achieved between the numerical simulations and the experimental data.