A CCD Imager Using ZnSe-Zn1-xCdxTe Heterojunction Photoconductor

A new CCD imager, having ZnSe-ZnCdTe heterojunction photoconductor as a photosensor which is vacuum-deposited on the CCD scanner, has been fabricated. The device has 404 (H) × 506 (V) scanning elements, each element measures 24 µm(H) by 14 µm(V), and the imaging area is 9.0 mm(H) × 6.7 mm(V) in size which is applicable to 2/3 inch camera format. The CCD scanner is fabricated with denuded zone which defines the defect-free device. A glass-reflow process is introduced to obtain the high breakdown of the heterojunction diode. The experimental result are as follows,; The sensitivity is 0. 16 µA/lx (3200 K). The horizontal and the vertical resolution are 280 and 450 TV lines, respectively. Dark current is 2 nA/cm2 for the photosensor (27°C). The signal to noise ratio is above 60 dB. The smearing suppression is effective for reducing the blooming phenomenon under the intense light illumination. The successful blooming suppression is achieved by this PLOSS structure device with metal screen grid. The high light exposure is allowable up to 1000 times as intense as the saturation exposure.