Three-terminal charge-injection device

A new configuration of the charge-injection device (CID) image sensor is described in this paper. Readout is performed by means of buried stripes (e.g., p stripes in an n-type substrate) acting as collectors of the injected minority carriers previously stored under the gates. This scheme provides separate paths for the displacement and diffusion currents and consequently improves the signal-to-noise (S/N) ratio. Furthermore, the new configuration yields simple X-Y selection without the need for extra crosspoint switches. In the present device, a word organized readout is achieved by means of polysilicon stripes perpendicular to the buried p stripes. The silicon area therefore can be used very efficiently.