A pixel includes a semiconductor layer with a charge accumulation layer extending in the semiconductor layer. A transistor has a read region penetrating into said semiconductor layer down to a first depth. An insulating wall penetrates into the semiconductor layer from an upper surface and containing an insulated conductor connected to a node of application of a potential. The insulating wall includes at least a portion provided with a deep insulating plug penetrating into the insulated conductor down to a second depth greater than the first depth. A continuous portion of the insulating wall laterally delimits, at least partially, a charge accumulation area and includes a wall portion with the deep insulating plug at least partially laterally delimiting the read region of the transistor.