NONVOLATILE SEMICONDUCTOR STORAGE DEVICE AND ITS MANUFACTURE

摘要

PROBLEM TO BE SOLVED: To suppress the variation of the kinetic energy of implanted ions to improve the manufacturing yield by providing at least one deposit layer as floating gates and setting the floating gate thickness to specified value or less. SOLUTION: A polycrystalline Si layer 5 is deposited on a floating gate- forming polycrystalline Si layer 4 for using it as an ion implanting deposit layer and permeating film such that the floating gate-forming Si layer 4 of 500-1000Åin mean thickness is deposited at a substrate temp. of 600-620 deg.C, using SiH4 as a raw material gas, the depositing Si layer 5 of 500-100Åin mean thickness and 300-500Åin grain size is deposited at a substrate temp. of 550-580 deg.C, using SiH4 as a raw material gas, and ions are implanted at an accelerating voltage of 15 keV-30 keV and dose of 1×10<11> /cm<2> -1×10<15> /cm<2> , using this Si layer 5 as a permeating film.