PURPOSE: To obtain a non-volatile memory cell, in which electrons can be injected into its floating gate by the use of a voltage smaller than conventionally, by using an ion implantation method to form P type source and drain regions on both outer sides of a floating gate electrode.

CONSTITUTION: On a required part of a silicon substrate 101, an N-type silicon region 102 is formed higher in its impurity concentration than the substrate, and next a field oxide film 103 and a gate oxide film 104 are formed on the region 102. In succession, polycrystalline silicon is deposited on the whole surface of the oxide film, and an ion implantation method or a heat diffusion method are used to diffuse an N type impurity e.g., phosphorus so that the polycrystalline silicon is made to be of an N-type. Further an N-type polycrystalline silicon electrode 105 is formed by a photolithographic method. While the N-type polycrystalline silicon electrode 105 is used as a mask, an ion implantation method is used to introduce a P-type impurity 108 e.g., boron on both outer sides of the N-type polycrystalline silicon electrode 105, serving as a chief surface part of the gate oxide film 104, so that a P-type source 106 and a drain 107 are formed.