CMOS image sensors in space: From OCO3 to LUVOIR by way of the Z machine

CMOS image sensors (CIS) have several significant advantages for NASA missions. Among the challenges for larger NASA payloads, including flagship mission concepts such as LUVOIR and Habex, are requirements for CIS detectors with small pixels, single photon sensitivity, and integration into large area mosaic focal planes. Key to these challenges is the emerging technology of 3D stacked CMOS image sensors. In this paper, we report the latest results from a collaboration between JPL and SNL to develop 3D-stacked, superlattice-doped CIS detectors for imaging and spectroscopy of high intensity, pulsed X-ray sources. JPL’s MBE-grown surface passivation layers are two orders of magnitude thinner and more highly doped than the ion-implanted layers in Sandia’s previous generation of detectors. JPL and Sandia demonstrated 3D-stacked, superlattice-doped photodiodes with 10x higher efficiency, marking a key milestone on the road toward gigapixel focal planes with single photon sensitivity.