Charge Transport and Storage Effect of Gold Ion Implanted Silicon Dioxide MOS Structure

Abstract

When gold ions of sufficiently high dose (~10^14 ions/cm^2) are implanted into thermally grown silicon dioxide MOS structure, novel charge transport and memory effect have been observed. For a typical structure with 800Å SiO2 and a projected ion range of 400Å, most of the induced interface states can be annealed out at 400℃. The charge transport in the implanted oxide is found to follow the Frenkel-Poole emission process with trapping energy level at 1.21 eV from the conduction band. Since the charge transport in the inner part of the oxide is by the Fowler-Nordheim tunneling mechanism, the MOS structure is equivalent to a double -layer memory device in which charges can be stored at the trapping centers inside the oxide when voltages are applied . Effects of oxide thickness, ion dose level, annealing temperature, and measurment temperature have been studied. Good agreements have been obtained between experimental results and theoretical predictions.