Bi-dimensional ballistic model of a trap capture cross-section

Electron traps are usually induced by defects and create levels in the forbidden gap, from which they can capture or reemit carriers into the nearest band. In the case of a thin insulating layer (<10 nm) used in electrical erasable programmable read only memory (EEPROM), traps are generated by stresses created by an electrical field, which could 106–107 V/cm yet. These stresses induce a leakage current call stress induced leakage current. Traps are generally defined by their density, energy, constant trapping time, and capture cross section. When the electrical field ⩾5 × 108 Vm−1, we take into account the influence of such electrical fields on the trap parameters and in particular the capture cross-section. By using a numerical ballistic model, we have plotted the free electron motion submitted to a constant electrical field and an attractive coulombian potential. With this model we show that the capture cross-section radius, varies inversely with the square root of the electrical field, and is dependent on the temperature. By the introduction of a potential well screening, it is possible to have a description of the trapping time.