Imaging device having enhanced quantum efficiency

In an imaging device of the type including a silicon target having a first surface with an input sensing region and a second surface with a charge storage region, a pontential barrier in the sensing region for controlling the blooming within the sensing region, a passivation region within the sensing region for stabilizing the atomic energy level along the first surface, and an anti-reflection region on said passivation region for reducing reflection and increasing absorption of light incident upon said device, the improvement wherein

• said anti-reflection region is formed of first and second contiguous layers, said first layer being formed of material which is non-interactive with silicon, said first layer of material being disposed on said first surface of said silicon target, said first layer of material having an index of refraction ranging from about 2.3 to 2.4 which is less than that of said silicon wafer and said second layer being formed of a material having an index of refraction ranging from about 1.32 to 1.35 which is lower than that of said first layer, and said first and second layers each having an optical thickness substantially equal to a quarter of the wavelength of light incident upon said device.