Influence of cerium-doping on the structural and electrical properties of hafnium oxide gate dielectric

摘要

The undoped and cerium-doped hafnium oxide (HfO_2) thin films have been deposited on p-type single crystal Si(100) substrates using radio frequency magnetron sputtering method. The structure and electrical properties have been investigated as a function of doping concentration. The results show that cerium serves effectively as a dopant to induce the crystallographic change from the monoclinic to the cubic phase. The ceium-doped HfO_2 shows higher dielectric constant than undoped HfO_2. The dielectric constant enhancement can be explained by the shrinkage of molar volume and the increase of molar polarizability. Compared with undoped HfO_2, the cerium-doped HfO_2 exhibits a lower leakage current due to the decrease of the oxygen vacancies number.