| 摘要 |
PURPOSE:To obtain a vertical acceleration type low voltage program nonvolatile memory having the high efficiency of injection, enabling easy reading and having high reliability by making thickness in the lateral direction of an insulating film on the side surface of a floating gate electrode thicker than that in the lengthwise direction of the insulating film in the upper section of the electrode. CONSTITUTION:An insulating film 4 is formed on the surface of a semiconductor substrate 1 to which a source region 2 and a drain region 3 are shaped, a polycrystalline silicon film is deposited, and a floating gate electrode 5 is formed through patterning. An insulating film is deposited or grown, and the insulating film 6 is left on the side wall surface of the floating gate electrode through etching. Insulating films 7, 9 are shaped, and an electrode 8 for erasing and a selective gate electrode 10 are formed. The film thickness tox2 of the insulating film 7 is used as a parameter important for determining erasing voltage, an erasing time, etc., and film thickness tox1 in the lateral direction of the insulating film 6 improves the efficiency of injection, and is employed as a parameter representing easy reading. |
