ION IMPLANTATION-INDUCED NANOSCALE PARTICLE FORMATION IN Al_2O_3 AND SiO_2 VIA REDUCTION

摘要

A novel method for creating nano-dimensional metallic precipitates in oxide materials using the technology of ion implantation is reported. The reduction of single-crystalline alumina to Al and fused silica to Si is induced by ion implantation with ions which are selected in accordance with the laws of ther- modynamics. The Al and Si resulting from reduction subsequently cluster and react with other elements to form nano-dimensional precipitates. The implantation of 150 keV Y+ and Ca+ into alumina to a fluence of 5 x 10~16 ions/cm~2, results in Al particles with an average diameter of 12.5 nm and 8.0 nm, respectively. Alumina implanted with Mg+ at the same ion energy and fluence forms MgAl_2O_4 platelets ranging from 5 to 10 nm in width and between 15 and 40 nm in length. The implantation of silica with 160 keV Zr+ ions to a fluence of 1 x 10~17 Zr+/cm~2, results in the formation of ZrSi_2 particles ranging in size between 1 and 17 nm. Consistent with thermodynamic predictions, control implants of Cr+ and Si+ in alumina and Cr+ in silica do not result in the formation of particles that contain elements originally present in the substrate.