Analysis of damaged region of carbon implanted alumina

Implantation was performed on surface-polished and thermal-treated alumina discs with 75 keV monocharged carbon ions at doses of 1 x 10(17) and 5 x 10(17) ions cm(-2). The alumina targets were kept at room temperature. The structural modifications induced during ion irradiation were studied by the scanning and scanning transmission electron microscopes. Alumina is readily amorphized at room temperature with carbon ions. The width of the ion-beam induced disordered area increases with ion dose. As it was established by selected area electron diffraction and electron energy loss spectra, low implanted specimens still show subsurface crystalline areas whose diffraction patterns could be assigned to a deformed structure of alumina. This deformed belt is shown beneath the amorphous region on highly implanted samples. Electron energy loss spectroscopy allows to follow the carbon line profile from surface into the bulk material, pointing the maximum concentration of implanted ion on the lower half of the amorphous region. Structural changes of Al(2)O(3) caused by carbon ion irradiation were corroborated with X-ray photoelectron spectroscopy. The X-ray photoelectron spectroscopy experiments showed that the oxygen concentration in the vicinity of the implanted alumina surface was reduced suggesting that this element was selectively sputtered by carbon irradiation. As a function of depth, peaks referring to Al-O bindings diminish while contributions of reduced aluminium and metal carbides were found, reaching the corresponding maxima at a depth of about 130 nm.