China’s Einstein Probe (EP) mission is designed for time-domain astrophysics with energy band of 0.5-4 keV. The payloads of EP include a wide-field X-ray telescope (WXT) and a follow-up X-ray telescope (FXT). The field of view (FOV) of WXT is about 3600 square degrees with sensitivity at least 10 times better than traditional X-ray all-sky monitors applying collimators or coded-masks. Back-side illuminated scientific CMOS (BSI sCMOS) is the best choice for WXT after several types of X-ray detectors are investigated. In this work, we study a BSI sCMOS sensor, GSENSE400BSI developed by Gpixel Inc., which is treated as a pathfinder for the focal plane detector of WXT. GSENSE400BSI has a pixel array of 2048×2048 with pixel size of 11 μm. We have characterized this BSI sCMOS as an X-ray detector. Based on the excellent performance of GSENSE400BSI, a new BSI sCMOS device with large sensitive area of 6×6 cm2 has been proposed as the focal plane detector for WXT.
Benefiting from motion blur free, Global shutter pixel is very widely used in the design of CMOS image sensors for high speed applications such as motion vision, scientifically inspection, etc. In global shutter sensors, all pixel signal information needs to be stored in the pixel first and then waiting for readout. For higher frame rate, we need very fast operation of the pixel array. There are basically two ways for the in pixel signal storage, one is in charge domain, such as the one shown in , this needs complicated process during the pixel fabrication. The other one is in voltage domain, one example is the one in , this pixel is based on the 4T PPD technology and normally the driving of the high capacitive transfer gate limits the speed of the array operation. In this paper we report a new 9T global shutter pixel based on 3-T partially pinned photodiode (PPPD) technology. It incorporates three in-pixel storage capacitors allowing for correlated double sampling (CDS) and pipeline operation of the array (pixel exposure during the readout of the array). Only two control pulses are needed for all the pixels at the end of exposure which allows high speed exposure control.
In this paper we present a 4 Megapixel high dynamic range, low dark noise and dark current CMOS image sensor, which
is ideal for high-end scientific and surveillance applications. The pixel design is based on a 4-T PPD structure. During
the readout of the pixel array, signals are first amplified, and then feed to a low- power column-parallel ADC array
which is already presented in . Measurement results show that the sensor achieves a dynamic range of 96dB, a dark
noise of 1.47e- at 24fps speed. The dark current is 0.15e-/pixel/s at -20oC.
High speed CMOS image sensors are very widely used in many applications
such as machine vision, robotic sensing and scientifically imaging etc. Flexibility in
design with CMOS technology allows the invention of various sensor architecture and
tricks which can improve the sensor speed. In this paper we discuss several
architectures for high speed sensors and their limitations.
This paper describes a back-side illuminated 1 Megapixel CMOS image sensor
made in 0.18um CMOS process for EUV detection. The sensor applied a so-call
"dual-transfer" scheme to achieve low noise, high dynamic range. The EUV
sensitivity is achieved with backside illumination use SOI-based solution. The
epitaxial silicon layer is thinned down to less than 3um. The sensor is tested and
characterized at 5nm to 30nm illumination. At 17.4nm targeted wavelength, the
detector external QE (exclude quantum yield factor) reaches almost 60%. The
detector reaches read noise of 1.2 ph- (@17.4nm), i.e. close to performance of EUV
In this paper, we address the issues of designing a CMOS image sensor for space applications. The
performance of a 4T pinned photodiode pixel under irradiation is shown and an example of a CMOS image
sensor designed for sun tracking is given. It has been shown that the radiation tolerance level of the pixel is
improved by using more advanced pixel architecture and more advanced fabrication process. Special measures are required in the sensor design to increases the sensor immunity on single event upset and
This paper describes a 2.2 Megapixel CMOS image sensor made in 0.18 μm CMOS process for high-speed
machine vision applications. The sensor runs at 340 fps with digital output using 16 LVDS channels at
480MHz. The pixel array counts 2048x1088 pixels with a 5.5um pitch. The unique pixel architecture supports
a true correlated double sampling, thus yields a noise level as low as 13 e- and a pixel parasitic light
sensitivity (PLS) of 1/60 000. The sensitivity of the sensor is measured to be 4.64 Vlux.s and the pixel full well
charge is 18k e-.
It is generally known that active pixel sensors (APS) have a number of advantages over CCD detectors if it comes to cost
for mass production, power consumption and ease of integration. Nevertheless, most space applications still use CCD
detectors because they tend to give better performance and have a successful heritage. To this respect a change may be at
hand with the advent of deep sub-micron processed APS imagers (< 0.25-micron feature size). Measurements performed
on test structures at the University of Delft have shown that the imagers are very radiation tolerant even if made in a
standard process without the use of special design rules. Furthermore it was shown that the 1/f noise associated with deep
sub-micron imagers is reduced as compared to previous generations APS imagers due to the improved quality of the gate
oxides. Considering that end of life performance will have to be guaranteed, limited budget for adding shielding metal
will be available for most applications and lower power operations is always seen as a positive characteristic in space
applications, deep sub-micron APS imagers seem to have a number of advantages over CCD's that will probably cause
them to replace CCD's in those applications where radiation tolerance and low power operation are important