Semiconductor-Type Auto-Exposure Control Sensor with a Schottky Barrier for Radiography Application

Digital radiography using the Auto-Exposure Control (AEC) function improves radiologic image quality. The most commonly used AEC sensor is the ion chamber type, which is associated with several problems. First, the thickness and size of these types cannot be further reduced. Second, when mechanical errors occur or when the ion gas injection mechanism is damaged by external impact, partial replacement cannot be performed, and the X-ray reaction area becomes limited. Therefore, this paper presents the development of a metal-silicon AEC sensor of the photoconductor element type based on the Schottky barrier effect. After processing, the sensors were characterized with an X-ray signal integrated in a five unit multicell zig test device. Based on these processes, we performed electrical characteristic, morphology, and transmission efficiency tests, as well as latent image analysis. The most basic results of electrical characteristic tests showed that the R-2 values of the aluminum (Al) silicide AEC sensors were 0.999 and 0.994 respectively, indicating that the proposed sensors exhibited similar or slightly better linearity than that of the commercial sensor. Evaluations of the proposed Al and Pt AEC sensor characteristics showed their applicability in diagnostic X-ray and mammography devices.