Abstract: A method of manufacturing a back-side (14) illuminated image sensor (1) is disclosed, comprising the steps of: starting with a wafer (2) having a first (3) and a second surface (4), providing light sensitive pixel regions (5) extending into the wafer (2) from the first surface (3), securing the wafer (2) onto a protective substrate (7) such that the first surface (3) faces the protective substrate, the wafer comprising a substrate of a first material (8) with an optical transparent layer (9) and a layer of semiconductor material (10), wherein the substrate (8) is selectively removed from the layer of semiconductor material by using the optical transparent layer (9) as stopping layer. For back-side illuminated image sensors, light has to transmit through the semiconductor layer and enter into the light sensitive pixel regions (5). In order to reduce absorption losses, it is very advantageous that the semiconductor layer (10) can be made relatively thin with a good uniformity.

Abstract: 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.