Fig. 5.26 shows the input structure for the ion implantation. It is one half of an NMOS-Transistor, which is cut through the gate. The crystalline silicon substrate is partly covered by a thick silicon dioxide layer forming the isolation and a thin silicon dioxide layer serving as the gate oxide and as a scattering oxide for the implantation. The gate is made of polysilicon which is also covered by a thin silicon dioxide layer.