| 摘要 |
PURPOSE:To prevent the lowering of the capacitance of a capacitor even when a planar area is reduced by using the vapor phase etching of polycrystalline Si by HF anhydride gas as a means through which electrode structure is formed to be an I type and a recessed section in the electrode structure is shaped. CONSTITUTION:An opening 10 is formed to approximately the upper section of a source region 6, polycrystalline Si 11 containing phosphorus is shaped so that polycrystalline Si 7 including phosphorus is not etched, and polycrystalline Si 11, polycrystalline Si 9, Si3N48 and polycrystalline Si 7 are etched continuously, thus forming a specified pattern. Treatment by hydrogen fluoride anhydride (HF) gas is executed, polycrystalline Si 9 containing no phosphorus is removed selectively, and exposed Si3N48 is removed through etching, thus shaping a capacitor lower electrode, which is composed of polycrystalline Si 7 and polycrystalline Si 11 containing phosphorus and a cross section of which takes an I type. A capacitor insulating film 12 and polycrystalline Si 13 are patterned, thus constituting an upper electrode for a capacitor. Accordingly, the lowering of the capacitance of the capacitor can be prevented. |
