| 摘要 |
PURPOSE:To obtain a photo transistor small in charging capacitance and high in operational speed by a method wherein a second emitter is additionally provided besides a base, a collector, and a first emitter. CONSTITUTION:A photo transistor is structured so as to be additionally provided with another emitter 7(access gate) besides a base 2, an emitter 3 and a collector 1. The second emitter 7 is provided ring-shapedly so as to surround the first emitter 3, whereby the sensitivity distribution in a pixel is rendered to be improved in uniformity. An access gate 7 through which a charging current flows is an emitter diffusion layer formed on a base diffusion layer, wherefore the junction area is small and moreover there is no direct capacitance between the gate 7 and a substrate 5. By these processes, the photo transistor of this design can be rendered extremely smaller in a charging capacity and completely charged at higher speed as compared with a usual photo transistor formed into IC. |
