SEMICONDUCTOR MEMORY CELL

摘要

PURPOSE:To form capacitor sections and an isolation region by a small area by shaping the capacitor sections for adjacent two memory cells and the isolation region for the two memory cells into one groove formed to a semiconductor substrate. CONSTITUTION:Polycrystalline silicon 20 given reference potential functions as a capacitor electrode for two memory cells while it also serves as an isolation region for the two memory cells. Charges are stored in polycrystalline silicon 17 buried into a groove (h). A semiconductor substrate 11 in high concentration also functions as the capacitor electrode together with the polycrystalline silicon 20. Potential at which the semiconductor substrate in the bottom of the groove does not invert must be applied to the polycrystalline silicon 20 in order to give the polycrystalline silicon 20 an isolation function. Since the semiconductor substrate 11 in high concentration through which the interface between the semiconductor substrate 11 in high concentration and an silicon dioxide film 19 is not brought into a depletion state even under the state in which high potential is memorized to the polycrystalline silicon 17 as a charge storage region, the polycrystalline silicon 20 sufficiently fulfills an isolation function by previously bringing the polycrystalline silicon 20 to a grounding level.