| 摘要 |
PURPOSE:To enhance the characteristic of holding charges by changing the film quality of an insulation film by a method wherein a non single crystal film is deposited over the entire surface after forming a thermal oxide film on the exposed surfaces of a floating gate electrode and a control gate electrode, thus being left on the side surfaces of each gate electrode and each insulation film by anisotropic etching, and converted into a thermal oxide film at the time of forming the source and drain regions. CONSTITUTION:After forming an element isolation film 22 on the surface of the surface of a P type Si substrate 21, the control gate electrode 23, a gate oxide film 24, the floating gate electrode 25 and a gate oxide film 26 are formed. Next, the thermal oxide film 27 is formed on the surfaces of the electrodes 23, 25 and the substrate 21. Then, a polycrystalline Si film 28 is removed by anisotropic etching after being deposited, thus forming a remnant polycrystalline Si film 28'. Thereafter, said oxide film 27 is removed by etching, and the source region 29 and the drain 30 are formed by ion implantation. At this time, the film 28' is converted into the thermal oxide film 31, and said oxide film 31 is formed also on the surface of the substrate 21 and the upper surface of the electrode 23. After depositing a PSG film 32 over the entire surface, Al wirings 34 and 34 are formed by opening holes. Thereby, the characteristic of holding charges can be improved. |
