Characterization and Comparison of Lateral Amorphous Semiconductors with Embedded Frisch Grid Detectors on 0.18um CMOS Processed Substrate for Medical Imaging Applications

摘要

An indirect digital x-ray detector is designed, fabricated, and tested. The detector integrates a high speed, low noise CMOS substrate with two types of amorphous semiconductors on the circuit surface. Using a laterally oriented layout a-Si:H or a-Se can be used to coat the CMOS circuit and provide high speed photoresponse to complement the high speed circuits possible on CMOS technology. The circuit also aims to reduce the effect of slow carriers by integrated a Frisch style grid on the photoconductive layer to screen for the slow carriers. Simulations show a uniform photoresponse for photons absorbed on the top layer and an enhanced response when using a Frisch grid. EQE and noise results are presented. Finally, possible applications and improvements to the area of indirect x-ray imaging that are capable of easily being implemented on the substrate are suggested.