High temperature electrical conduction in nanoscale hafnia films under varying oxygen partial pressure

Abstract

Point defect equilibration in nanocrystalline hafnium oxide thin films in the monoclinic (m-HfO(2)) phase was studied by electrochemical measurements performed under varying temperature and oxygen partial pressure (P(O2)) on films of 35-63 nm thickness on single crystal MgO and Al(2)O(3) substrates. The conductance varied as (P(O2))(n), where n is the in the range similar to+1/11 to similar to+1/14, at high P(O2). The increasing conductance with P(O2) suggests that the electronic conduction in the HfO(2) films is p-type and oxygen interstitials or hafnium vacancies, rather than oxygen vacancies, could be dominant charged point defects in nanocrystalline, undoped m-HfO(2) films. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3482940]