Compact detection array having improved polarization conditions
An array of photodetector is organized along a first organizational axis on a semiconductor substrate of a first conductivity type. Each photodetector is at least partially formed in the substrate which forms a first electrode of the photodetector. A peripheral polarization ring is formed around the array of photodetectors. The polarization ring is connected to a polarization voltage generator and to the substrate. A read circuit is connected to a photodetector via the second terminal of the photodetector. A first switch connects the photodetector to a generator of an additional voltage. A second switch connects the photodetector to the associated read circuit. The first and the second switches are in opposite states.
1. A detection device comprising:
a semiconductor substrate of a first conductivity type,
an array of photodetectors organized along a first organizational axis, each photodetector being at least partially formed in the semiconductor substrate, said semiconductor substrate forming a first terminal of the photodetectors,
a peripheral polarization ring formed around the array of photodetectors, the polarization ring being connected to the substrate and to a generator configured for providing a polarization voltage,
a plurality of readout circuits connected to a second terminal of the photodetectors,
a first switch connected between one of the readout circuits and the second terminal of the associated photodetector so as to authorize or to block transmission of an electric current representative of an observed scene emitted by the photodetector,
a second switch connected between a second generator configured for providing an additional voltage and the second terminal of said associated photodetector so as to apply the additional voltage to the second terminal, the first and second switches being in opposite states, and
an electrically-conductive contact connected to the semiconductor substrate by an area in doping continuity with the semiconductor substrate,
wherein the electrically-conductive contact is connected to one of the readout circuits by a first switch and to the second generator by a second switch so as to apply the additional voltage to the semiconductor substrate, the first and second switches being in opposite states, and
wherein the electrically-conductive contact is arranged between two photodetectors in the first organization axis, the distance separating the electrically-conductive contact from each of the two photodetectors being equal to the distance separating two adjacent photodetectors along the first organizational axis.
2. The device according to claim 1 , wherein the second generator is the first generator.
3. The device according to claim 1 , wherein each photodetector has a second terminal connected to an input of one readout circuit.
4. The device according to claim 3 , wherein the second terminal of each photodetector is connected to the second generator by a second switch, the photodetector being connected to the associated readout circuit by a first switch being in an opposite state.
5. The device according to claim 1 , wherein the second switch is in an on state.
6. The device according to claim 5 , comprising a plurality of electrically-conductive contacts connected to the semiconductor substrate along the first organization axis, the electrically-conductive contacts being arranged between the photodetectors at regular intervals, according to a first repetition pitch which is a multiple of a repetition pitch of the photodetectors.
7. The device according to claim 1 , comprising a plurality of electrically-conductive contacts connected to the semiconductor substrate along the first organization axis, the electrically-conductive contacts being arranged between the photodetectors at regular intervals, according to a first repetition pitch which is a multiple of a repetition pitch of the photodetectors.
8. The device according to claim 1 , wherein the photodetectors are formed by a first doped area of a second conductivity type in the semiconductor substrate to form a P/N- or N/P-type junction and wherein the electrically-conductive contact comprises no first doped area.
9. The device according to claim 1 , wherein the photodetectors are formed by a first doped area of a second conductivity type in the semiconductor substrate to form a P/N- or N/P-type junction and wherein the electrically-conductive contact comprises a second doped area of the first conductivity type shorted with a third doped area of the second conductivity type.