Method of making a large area imager with improved signal-to-noise ratio

A method of making an x-ray imaging device including an array of semiconductor switching elements, the method comprising the steps of:

• a) providing a substrate;
• b) forming an array of semiconductor based switching elements and corresponding address lines on the substrate, each switching element including a first capacitor electrode associated therewith:
• c) covering said first capacitor electrodes with a dielectric layer;
• d) depositing an organic photo-imageable insulating layer having a dielectric constant value of less than about 5.0 onto the substrate over the switching elements to a thickness of from about 1.0 to 4.0 .mu.m;
• e) photo-imaging the insulating layer in order to form a first group of vias or contact holes therein, each via in the first group corresponding to one of the switching elements;
• f) forming an array of collector electrodes over the photo-imaged insulating layer so that each collector electrode communicates with one of the switching elements through a corresponding one of the vias in the insulating layer, each said collector electrode overlapping a portion of a corresponding first capacitor electrode within a corresponding one of the vias formed in the insulating layer, said first dielectric layer being disposed between the collector electrodes and the capacitor electrodes, thereby forming storage capacitors associated with said switching elements;
• g) forming a photoconductive layer over the collector electrodes;
• and
• h) forming a conductive layer on the substrate in a location so that the photoconductive layer is located between the conductive layer and the collector electrodes, so that the storage capacitors are able to store charge as a function of incident radiation received by corresponding collector electrodes.