IMAGE SENSOR, CAMERA SYSTEM COMPRISING THE IMAGE SENSOR AND METHOD OF MANUFACTURING SUCH A DEVICE

摘要

An image sensor (1) having a semiconductor body (2) with a first conductivity type and having a surface (3), the surface being provided with a number of cells (4), a cell comprising a photosensitive element (5) and a reset transistor (6), the reset transistor comprising a source region (7), a drain region (8) and a gate region (9), the source region (7) and the drain region (8) having a second conductivity type opposite to the first conductivity type, the source region (7) of the reset transistor (6) being electrically connected to the photosensitive element (5). There is a well region (10) present which well region extends from the surface (3) into the semiconductor body (2) and extends at least partly below the gate region (9) and the well region has a first conductivity type. The source region (7) extends at least substantially in a doped region (11) of the photosensitive element (5), the doped region (11) having a second conductivity type. The reduction of the source-well junction area reduced the number of white pixels and fixed pattern noise. In the method of manufacturing the image sensor, the well region (10) is positioned partly below the gate region (9) so that there is a distance (13) between the highly doped source region (7) and the well region (10). The distance (13) increases the depletion layer width between the source and well junction, so that tunnel currents no longer dominate the leakage currents and the related number of white pixels and fixed pattern noise are reduced.