| 摘要 |
PURPOSE:To decrease short circuits between gate electrodes and improve transfer properties, by coating thicker oxide films than other oxide films, on the side faces of polycrystalline Si film gate electrodes which constitute a charge transfer unit. CONSTITUTION:An SiO2 film 2 is coated on an Si substrate 1. A polycrystalline Si film doped with an impurity for electrodes is deposited on the film 2 and made into a pair of comb-shaped gate electrodes 3a, 3b by photolithography. Heat treatment is then effected to produce thick SiO2 films 2a wrapping the electrodes 3a, 3b. Dry etching is performed by CF4 gas to remove the films 2a from the exposed film 2 and the tops of the electrodes 3a, 3b and leave the films 2a only on the side faces of the electrodes. Thin SiO2 films 2b of the same thcikness as the film 2 are coated on the exposed surfaces of the electrodes 3a, 3b. Comb-shaped metal film gate electrodes 4a, 4b are coated over the edges of the electrodes 3a, 3b and on the film 2 in recesses. This results in preventing the vaporization of the impurity from the side faces of the electrodes 3a, 3b. |
