| 摘要 |
PURPOSE:To inhibit a crystal defect and the spread of trench width by forming MOS capacitors by utilizing the side walls of the trenches and burying capacitor electrodes consisting of polysilicon, etc., into all trenches through insulating films. CONSTITUTION:A first mask material 31 is shaped onto a transistor forming region in a first conductivity type semiconductor substrate 11, and the surface of the substrate 11 is etched selectively by using the mask material 31 and trenches 13 for element isolation are formed. Second conductivity type impurity introducing layers are shaped onto the bases and side surfaces of capacitor forming regions in the trenches 13, second mask materials 34 are formed onto the side walls of the trenches 13, and the bottoms of the tenches 13 are etched selectively by employing the first and second mask materials 31, 34 and the impurity introducing layers shaped onto the bases of the trenches 13 are removed. The second mask material 34 is gotten rid of and insulating films 14 are formed onto the wall surfaces of the trenches 13, capacitor electrodes 15 are buried and shaped into the trenches 13, the first mask material 31 is taken off, and a MOS transistor is formed into the transistor forming region. Accordingly, the generation of a crystal defect is inhibited, and the spread of the trenches is prevented. |
