Characterization of Three-Dimensional-Integrated Active Pixel Sensor for X-Ray Detection

We have developed a back-illuminated active pixel sensor (APS) which includes an SOI readout circuit and a silicon diode detector array implemented in a separate high-resistivity wafer. Both are connected together using a per-pixel 3-D integration technique developed at Lincoln Laboratory. The device was fabricated as part of a program to develop a photon-counting APS for imaging spectroscopy in the soft X-ray (0.3-10-keV) spectral band. Here, we report single-pixel X-ray response with spectral resolution of 181-eV full-width at half-maximum at 5.9 keV. The X-ray data allow us to characterize the responsivity and input-referred noise properties of the device. We measured interpixel crosstalk and found large left-right asymmetry explained by coupling of the sense node to the source follower output. We have measured noise parameters of the SOI transistors and determined factors which limit the device performance.