Abstract: A Rat IgG antibody film, formed on a p-type Si substrate, is selectively irradiated with ultraviolet rays, thereby leaving part of the Rat IgG antibody film, except for a region deactivated with the ultraviolet rays. Next, when the p-type Si substrate is immersed in a solution containing Au fine particles that have been combined with a Rat IgG antigen, the Rat IgG antigen is selectively combined with the Rat IgG antibody film. As a result, Au fine particles, combined with the Rat IgG antigen, are fixed on the Rat IgG antibody film. Thereafter, the p-type Si substrate is placed within oxygen plasma for 20 minutes, thereby removing the Rat IgG antibody film, the deactivated Rat IgG antibody film and the Rat IgG antigen. Consequently, dot elements can be formed at desired positions on the p-type Si substrate. If these dot elements are used for the floating gate of a semiconductor memory device, then the device has a structure suitable for miniaturization.