Semiconductor storage

A semiconductor storage device comprising:

• a first conductivity type semiconductor part (11, 111, 111a, 72, 189) composed of any one of a semiconductor substrate (11, 111, 111a), a well region provided in a semiconductor substrate and a semiconductor film (72, 189) disposed on an insulator (71, 188);
• a gate insulating film (12, 114, 114a) formed on the first conductivity type semiconductor part;
• a gate electrode (13, 117, 117a) formed on the gate insulating film;
• charge holding portions (10A, 10B;
• 20A, 20B;
• 161, 162;
• 162a) formed on opposite sides of the gate electrode;
• second conductivity type diffusion layer regions (17, 18;
• 57, 58;
• 112, 113;
• 113a) formed in regions of the first conductivity type semiconductor part corresponding to the respective charge holding portions;
• and
• a channel region (31) below the gate electrode;
• wherein
• the charge holding portions (10A, 10B;
• 20A, 20B;
• 161, 162;
• 162a) are each constructed so as to change, in accordance with an electric charge amount held in the charge holding portions, a current amount flowing from one of the second conductivity type diffusion layer regions to the other of the diffusion layer regions through the channel region when a voltage is applied to the gate electrode (13, 117, 117a);
• and
• part of each charge holding portion (10A, 10B;
• 20A, 20B;
• 161, 162;
• 162a) is present below an interface of the gate insulating film (12, 114, 114a) and the channel region (31).