Electrical properties of metal–HfO 2–silicon system measured from metal–insulator–semiconductor capacitors and metal–insulator–semiconductor field–effect transistors using HfO 2 gate dielectric

Abstract

Metal–insulator–semiconductor (MIS) capacitors and metal–insulator–semiconductor field effect transistors (MISFETs) incorporating HfO 2 gate dielectrics were fabricated using RF magnetron sputtering. In this work, the essential structures and electrical properties of HfO 2 thin film were examined. The leakage current measured from MIS capacitors depends on the sputtering gas mixture and the annealing temperature. The best condition to achieve the lowest leakage current is to perform the annealing at 500 °C with a mixture of 50% N 2 and 50% O 2 gas ratio. Aluminum is used as the top electrode. The Al/HfO 2 and the HfO 2/Si barrier heights extracted from Schottky emission are 1.02 eV and 0.94 eV, respectively. An Al/HfO 2/Si energy band diagram is proposed based on these results.