Societe Francaise De Detecteurs Infrarouges-sofradir

Lynred

Patrick Maillart

Michel Zecri

Laurent Rubaldo

Fabien Chabuel

Michel Zécri

The circuit of detection of light radiation includes a photodetector. The photodetector is coupled to three capacitors by means of three switches. The capacitors are parallel mounted to form a capacitive load whose value of electrical capacity changes as a function of the openings/closures of the switches. This configuration allows to stabilize the voltage present on the output terminal in the detection circuit for a wider range of illumination sustained by photodetector.

Light-ray detection circuit

The detection device includes a semiconductor substrate of a first conductivity type. A matrix of photodiodes organized along a first organization axis is formed on the substrate. Each photodiode is at least partially formed in the substrate. A peripheral biasing ring is formed around the photodiode matrix. The biasing ring is connected to a bias voltage generator. An electrically conducting contact is connected to the substrate and arranged between two photodiodes on the first organization axis. The distance separating the contact from each of the two photodiodes is equal to the distance separating two adjacent photodiodes along the first organization axis. The contact is connected to the bias voltage generator.

Detection matrix with improved biasing conditions and fabrication method

In an infrared detector provided with a photodiode, when the temperature of the photodiode is lowered to its operating temperature, the photodiode is forward biased. During forward biasing of the photodiode, injection of a majority carrier current takes place through the photodiode. The majority carriers mask a part of the defects of the photodiode. The acquisition phase is then performed by reverse biasing the photodiode.

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La Murette, France

Patrick Maillart