CHARGE TRANSFER DEVICE MANUFACTURE

摘要

The invention resides in a method of manufactoring a C.T.D. comprising overlapping clock electrodes mutually isolated or separated by an intermediate oxide. The surface of the semiconductor body is covered with an oxide layer and a nitride layer on top of the oxide layer. A first set of clock electrodes of polycrystalline silicon is provided on the nitride layer. These poly-electrodes are subjected to an oxidation treatment to form the said intermediate oxide. During this oxidation, the gate oxide below the nitride layer does not become thicker, because of the nitride which ?ks the semiconductor body against the oxidation treatment. After the oxidation treatment, the nitride is removed partly, using the poly-electrodes as etching masks. In a subsequent step, a second set of clock electrodes between the polyelectrodes is provided on top of said gate oxide, said second clock electrodes overlapping partly the poly-electrodes and separated therefrom by a silicon oxide layer covering the polyelectrodes.