Band structure and electrical properties of Gd-doped HfO2 high k gate dielectric

Abstract

Effects of Gd doping on band gap, band offset, oxygen vacancies, and electrical properties of amorphous HfO2 film have been studied. The results show that Gd incorporation helps increase band gap, conduction band offset and conduction band minimum, and reduce oxygen vacancies simultaneously. Kept at the same physical thickness of 5 nm, Gd-doped HfO2 gate dielectric has a leakage current density of 9.0×10−4 A/cm2 at 1 V gate voltage, one and a half orders of magnitude lower than that of the pure HfO2. Gd doping also enhances the dielectric constant. The capacitance equivalent thicknesses of 0.98 nm and 0.81 nm for HfO2 and Gd-doped HfO2 films, respectively, have been obtained.