Stray light is a significant interference factor for many photodiode and array applications. It increases the signal background and thus negatively affects the sensitivity of the detectors and their signal-to-noise ratio. In photodiode arrays, it also contributes to crosstalk between the individual optical channels. The surface of the detector itself represents a not insignificant source of scattered light. The aim of the project is therefore to develop a technology whose core element is a photostructurable, optically non-transparent coating. This is to be used to specifically protect critical areas on the surface of the silicon chip, in particular metallic structures, from unwanted light incidence. This is intended to reduce interfering lateral and environmental influences and increase the usable proportion of the detector signals. At the same time, the system-side effort required to suppress stray light and the calibration effort of the sensor systems is significantly reduced.
A key aspect of the technology development is the compatibility of the optically non-transparent coating with the necessary downstream processes for the construction of the sensors and their operating conditions. Photodiodes for turbidity and scattered light measurement and photodiode arrays for position sensors will serve as concrete application examples.
The research and development work described is being funded by the Federal Ministry for Economic Affairs and Climate Action (BMWK) in the research project “Photostructurable black paint against scattered light” (PuSch).
Funding code: 49 MF 230089