An Amorphous Si High Speed Linear Image Sensor

An amorphous silicon thin film linear image sensor of a sandwich structure has been developed. The sensor consists of a transparent ITO as an upper electrode, an a-Si: H layer and Cr or Al lower electrodes. The a-Si: H layer is formed by RF glow discharge. These layers are deposited on a glass or ceramic substrate. The sensor has good photoelectric characteristics as follows: Photo-sensitivity is 10-7 A/cm2 1x, photo-response time is less than 0.5 ms and photo- to dark-current ratio is larger than 3×103. The sensor can be operated by a -5 V single power source and this same power source can be used for the driving circuits. A 1056-bit, 8 bit/mm linear image sensor has been fabricated. Using the device, images of a document have been read and reproduced successfully.