Low Activation Energy by Polarization in a Floating Gate Structure

This paper describes a new and essential mechanism for the low activation energy of charge retention, based on the electrostatic energy change of the floating gate due to a decrease in the stored electrons. The electrostatic potential in the floating gate when a positive space charge is generated at the interface is given by Debye-Hückel. The electron cloud shifts and polarization arises. At this time, a pair consisting of a positive space charge and polarized electron cloud forms an exciton. An electron which forms an exciton recombines with a positive charge by tunneling through SiO2. As a result, the mechanism that an electron is emitted above the work function of 3.2 eV at the Si-SiO2 interface by supplying a thermionic activation energy of 1.2 eV has been revealed.