Temperature Dependence of the Tunnel-Emission Conduction Current in Metal- ZrO2-Silicon Capacitor Structures

Abstract

Zirconium oxide is considered as a potential replacement for due to its high dielectric constant. The metal-insulator-semiconductor capacitors were fabricated. The electrical conduction mechanism in zirconium oxide thin films as a function of temperature and electric field was studied. The temperatures measured were and from . With the Al electrode under negative bias, the conduction mechanism in the electric field of and at the temperature is found to be Fowler-Nordheim tunneling emission. The extracted barrier height between Al and is . At the electric field of and temperatures of , the electrical conduction is dominated by tunnel emission of trapped electrons with an extracted trap barrier height of at . The trap barrier height decreases as the temperature increases. This barrier height decreases linearly with temperature with a slope of about . The lowering of the barrier height is explained by bandgap reduced with increasing temperature.