RESUMEN
Image sensors are must-have components of most consumer electronics devices. They enable portable camera systems, which find their way into billions of devices annually. Such high volumes are possible thanks to the complementary metal-oxide semiconductor (CMOS) platform, leveraging wafer-scale manufacturing. Silicon photodiodes, at the core of CMOS image sensors, are perfectly suited to replicate human vision. Thin-film absorbers are an alternative family of photoactive materials, distinguished by the layer thickness comparable with or smaller than the wavelength of interest. They allow design of imagers with functionalities beyond Si-based sensors, such as transparency or detectivity at wavelengths above Si cutoff (e.g., short-wave infrared). Thin-film image sensors are an emerging device category. While intensive research is ongoing to achieve sufficient performance of thin-film photodetectors, to our best knowledge, there have been few complete studies on their integration into advanced systems. In this paper, we will describe several types of image sensors being developed at imec, based on organic, quantum dot, and perovskite photodiode and show their figures of merit. We also discuss the methodology for selecting the most appropriate sensor architecture (integration with thin-film transistor or CMOS). Application examples based on imec proof-of-concept sensors are demonstrated to showcase emerging use cases.
RESUMEN
Optical phased arrays (OPAs) with phase-monitoring and phase-control capabilities are necessary for robust and accurate beamforming applications. This paper demonstrates an on-chip integrated phase calibration system where compact phase interrogator structures and readout photodiodes are implemented within the OPA architecture. This enables phase-error correction for high-fidelity beam-steering with linear complexity calibration. A 32-channel OPA with 2.5-µm pitch is fabricated in an Si-SiN photonic stack. The readout is done with silicon photon-assisted tunneling detectors (PATDs) for sub-bandgap light detection with no-process change. After the model-based calibration procedure, the beam emitted by the OPA exhibits a sidelobe suppression ratio (SLSR) of -11â dB and a beam divergence of 0.97° × 0.58° at 1.55-µm input wavelength. Wavelength-dependent calibration and tuning are also performed, allowing full 2D beam steering and arbitrary pattern generation with a low complexity algorithm.
