Method and device for a cmos image sensor

A color sensing apparatus formed in a semiconductor substrate associated with a first conductivity type, the color sensing apparatus capable of detecting light corresponding to at least a first wavelength range and a second wavelength range, the first wavelength range corresponding to a first absorption depth, the second wavelength range corresponding to a second absorption depth, the color sensing apparatus comprising:

• a first region associated with a second conductivity type in the semiconductor substrate, the first region forming a junction within the semiconductor substrate at a junction depth, the junction depth being substantially equal to the first light absorption depth;
• a voltage supply configured to provide at least a first bias voltage and a second bias voltage between the first region and the semiconductor substrate such that a depletion region of the junction extends to a depletion depth equal to or larger than the first light absorption depth and the second absorption depth respectively;
• and
• a current sensing device configured to measure a first photocurrent and a second photocurrent corresponding to the first bias voltage and the second bias voltage, respectively.

A color sensing apparatus formed in a semiconductor substrate associated with a first conductivity type, the color sensing apparatus capable of detecting light corresponding to at least a first wavelength range and a second wavelength range, the first wavelength range corresponding to a first absorption depth, the second wavelength range corresponding to a second absorption depth, the color sensing apparatus comprising:

• a first region associated with a second conductivity type formed in the semiconductor substrate;
• a second region associated with the first conductivity type formed in the first region, the second region forming a junction within the first region at a junction depth, the junction depth being substantially equal to the first light absorption depth;
• an isolation region associated with the first conductivity type formed in the first region, the isolation region being configured to surround the junction and to extend through the depth of the first region;
• a voltage supply configured to provide at least a first bias voltage and a second bias voltage between the second region and the first region such that a depletion region of the junction extends to a depletion depth equal to or larger than the first light absorption depth and the second absorption depth respectively;
• and
• a current sensing device configured to measure a first photocurrent and a second photocurrent corresponding to the first bias voltage and the second bias voltage, respectively.