| 摘要 |
PURPOSE:To obtain a method, by which a capacitor groove is made to be an N type and a groove region for isolating elements, which are contacted with an MOS-transistor forming region is not made to be N-type, by forming the element isolating grooves and the capacitor groove, covering the element isolating grooves, and performing N<+> diffusion in the capacitor groove. CONSTITUTION:In a P-type semiconductor substrate, element isolating grooves 2 and a diffusing groove 3 is separately formed. Thereafter, P, As and the like are diffused from the diffusing groove 3. Heat treatment is performed. A part W between both grooves is filled with an N-type diffused layer 4. For P, POCL3 gas is heated. For Sb, Sb2O3 is heated. The evaporated gases are introduced into a heat diffusing furnace. For As, As glass, in which As is included in CVD SiO2, is deposited on the inner wall of the diffused groove and diffused. Thereafter, on the inner wall of the element isolating groove 2, an insulating film 5 comprising a single layer or multiple layers of an SiO2 or Si3N4 film is deposited. A plate 6 represented by polycrystalline Si is embedded. The groove 3 is buried back by the polycrystalline Si or single crystal Si, and a buried layer 7 is formed. Thus a flat diffused layer 4 is obtained. The N-type diffused layer 4 forms a capacitor together with the plate 6, with the insulating film 5 in-between. |
