High-exposure-durability, high-quantum-efficiency (>90%) backside-illuminated soft-X-ray CMOS sensor

We develop a high-quantum-efficiency, high-exposure-durability backside-illuminated CMOS image sensor for soft-X-ray detection. The backside fabrication process is optimized to reduce the dead-layer thickness, and the Si-layer thickness is increased to 9.5 μm to reduce radiation damage. Our sensor demonstrates a high quantum efficiency of >90% in the photon-energy range of 80–1,000 eV. Further, its EUV-regime efficiency is ~100% because the dead-layer thickness is only 5 nm. The readout noise is as low as 2.5 e− rms and the frame rate as high as 48 fps, which makes the device practical for general soft X-ray experiments.