SEMICONDUCTOR PHOTOSENSOR FOR INFRARED RADIATION

摘要

A photosensor for the detection of infrared radiation in the wavelength range of 1 to 1000 micrometers consists of a semiconductor substrate with a highly doped interaction volume for the incoming radiation. At the edge of this highly doped region, an extended gate electrode is placed consisting of a conducting material on top of an insulating layer. On the other side of the gate electrode, another highly doped semiconductor region is placed, acting as a charge collector. Through free carrier absorption in the interaction volume, incoming photons impart their energy on mobile charge carriers. In the case of free electrons, the gate electrode is biased slightly below the reset voltage of the interaction volume, so that the electrons carrying the additional energy of the absorbed photons can predominantly make the transition from the interaction volume across the gate electrode area to the charge collector volume.

主权项

1. A photosensor for detecting infrared radiation in the wavelength range of 1 to 1000 micrometers, comprising:
a main region of a semiconductor substrate; a highly doped interaction volume for the incoming radiation in the semiconductor substrate; an adjacent gate electrode including a conducting material on top of an insulated layer, the adjacent gate electrode being an extended structure adjacent to the interaction volume; and an adjoining highly doped collector region acting as a charge collector, the collector region essentially consisting of a highly doped semiconductor zone and being an extended structure adjacent to the gate electrode, wherein the interaction volume is electrically biased to a first voltage VB, the collector region is electrically biased to a second voltage VS, which is higher than the first voltage VB in case photo-excited electrons should be collected, and which is lower than the first voltage VB in case photo-excited holes should be collected, the incoming photons impart their energy through free carrier absorption on mobile charge carriers in the interaction volume, producing photo-excited electrons in case the free charge carriers are electrons, or producing photo-excited holes in case the free charge carriers are holes, the gate electrode is biased to a third voltage VG, so that a potential barrier for the photo-excited charge carriers in the interaction volume is created, such that the energy imparted by the incoming photons is sufficient for the photo-excited charge carriers to overcome the potential barrier, and the photo-excited charge carriers can be collected in the collector region for subsequent electronic detection.