| 摘要 |
PURPOSE: To provide the trench separating structure, which improves reliability and can form a high density integrated circuit. CONSTITUTION: On an Si substrate, a buffer layer and an etch stopping layer are formed. A groove (trench) is formed by anisotropic etching. The groove specifies an active region 23 in the substrate. A groove liner 28 is formed by thermal oxidation at the neighborhood of a groove-side wall 24 and a groove bottom 26. Ion implantation is performed at the lower substrate part of the groove bottom 26, and a channel stopping region 30 is formed. Then, groove filling material is formed of chemically evaporated SiO2 . A part of the filling material is selected and removed, and a groove plug 34 is formed. The surface is thermally oxidized, and a first dielectric layer 42 comprising SiO2 is formed on the active layer 23. The first dielectric layer can be Si oxide nitride. Furthermore, a second dielectric layer 44 of a thin SiO2 layer is formed on the first dielectric layer and the active region and the groove separating region 40. A transistor gate electrode 46 is formed on the layer 44. Since the thickness of the gate dielectric substance between the gate electrode and the groove corner is increased, the breakdown voltage of the gate dielectric substance on the groove corner is increased.
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