L. Calvobarrio et al., ION-BEAM SYNTHESIS OF ALUMINUM NITRIDE - CHARACTERIZATION OF THIN ALNLAYERS FORMED IN MICROELECTRONICS ALUMINUM, Materials science and technology, 11(11), 1995, pp. 1187-1190
Buried AIN thin layers have been formed by high nose N+ ion implantati
on into microelectronics grade Al films (containing 1 at.-%Si), which
were deposited on Si wafers. The structures obtained have been charact
erised by spreading resistance measurements, transmission electron mic
roscopy, secondary ion mass spectrometry, X-ray diffraction, and X-ray
photoelectron spectroscopy. The results show the formation of buried
dielectric precipitates of crystalline AIN at implantation doses below
the threshold and a continuous polycrystalline AIN layer at doses abo
ve the threshold. The AIN grains have the wartzute structure, sizes of
about 10-15 nm, and a preferred orientation in relation to the Al mat
rix, namely, [110](AIN) parallel to [110](Al). The data also show that
, under certain conditions, the main impurities (Si and O) are gettere
d in the buried layer. Moreover; for thin Al films, the formation of a
Si rich surface layer is observed. This surface layer is formed by Si
diffusion from the substrate, probably due to the penetration of N+ i
ons into the Si substrate. The distribution and evolution of these imp
urities and the different phases formed are studied as a function of t
he thickness and grain size of the Al film, as well as of the annealin
g processes. (C) 1995 The Institute of Materials.