Device design for global shutter operation in a 1.1-μm pixel image sensor and its application to near infrared sensing
Global shutter is a feature of some CMOS image sensors that allows capture of an entire image at a single point in time. We discuss how the device architecture of InVisage’s QuantumFilm enables global shutter operation by controlling the bias on the device stack without an additional transistor, giving high shutter efficiency in a 1.1 μm pixel CMOS image sensor. We use drift-diffusion device simulations to inform our design and reveal device and material properties that are key for carrier selectivity. Based on our device model, we fabricated global-shutter-enabled QuantumFilm devices for near infrared sensing applications and present a characterization of our devices.
Miniaturization of NIR/SWIR image sensors enabled by thin-film photodiode monolithic integration
In this paper, we present short-wave infrared (SWIR) image sensors with high pixel density. Quantum dot (QD) photodiode stack is monolithically integrated on custom, 130 nm node CMOS readout circuit. State-of-the-art pixel pitch of 1.82 μm is demonstrated in focal plane arrays sensitive at eye-safe region above 1400 nm wavelength. Thin-film photodiode (TFPD) technology will facilitate realization of ultra-compact SWIR sensors for future XR applications, including eye-safe tracking systems and enhanced vision.
Quantum dot-based image sensors for cutting-edge commercial multispectral cameras
This work presents the development of a quantum dot-based photosensitive film engineered to be integrated on standard CMOS process wafers. It enables the design of exceptionally high performance, reliable image sensors. Quantum dot solids absorb light much more rapidly than typical silicon-based photodiodes do, and with the ability to tune the effective material bandgap, quantum dot-based imagers enable higher quantum efficiency over extended spectral bands, both in the Visible and IR regions of the spectrum. Moreover, a quantum dot-based image sensor enables desirable functions such as ultra-small pixels with low crosstalk, high full well capacity, global shutter and wide dynamic range at a relatively low manufacturing cost. At InVisage, we have optimized the manufacturing process flow and are now able to produce high-end image sensors for both visible and NIR in quantity.