PAC and PALS study in the HfO2 + SiO2 system

CHAIN, C.Y; L. C. DAMONTE; S. FERRARI; E. MUÑOZ; C.E. RODRÍGUES-TORRES; A.F. PASQUEVICH

JOURNAL OF ALLOYS AND COMPOUNDS

ELSEVIER SCIENCE SA

Año: 2010 vol. 495 p. 527 - 531

0925-8388

A high-k HfO2/SiO2 gate stack is taking the place of SiO2 as a gate dielectric in field effect transistors. This fact makes the study of the solid-state reaction between these oxides very important. Nanostructure characterization of a high-energy ball milled and post-annealed equimolar HfO2 and amorphous SiO2 powder mixture has been carried out by perturbed angular correlations (PAC) technique. The study was complemented with X-ray diffraction and positron annihilation lifetime spectroscopy (PALS). The experimental results revealed that the ball milling of equimolar mixtures increases the defects concentration in hafnium oxide. No solid-state reaction occurred even after 8 h of milling. The formation of HfSiO4 (hafnon) was observed in the milled blends annealed at high temperatures.The PAC results of the milled samples are compared with those obtained for pure m-ZrO2 subjected to high-energy ball milling and with reported microstructure data for the system ZrO2–SiO2.