Semiconductor photodetector and method of operation.

摘要

The photodetector device (10) has a large detection area in combination with a low output capacitance. A photodetector system employing this device can provide low noise as a result of the device's low output capacitance. The device (10) preferably comprises a body (12) of semiconductor material of one conductivity type with a large detector region (22) of the opposite conductivity type disposed adjacent a major surface and with a substantially smaller output region (26) also of the second conductivity type disposed adjacent the same surface and spaced from the detector region. The detector region (22) is coupled to the output region (26) by an insulated gate electrode (34) which controls the potential underneath the gate electrode. The output region (26) is biased to reverse bias its PN junction with the body region and the gate electrode (34) is biased in the same polarity with a magnitude to maintain the channel region at a lesser potential so that the floating detector region is at a lesser potential than the output region and capacitively decoupled from the output region.