Abstract

In this work, we present the structural and electrical properties of HfO(2), HfO(2) + SiO(2), and HfO(2) + Al(2)O(3) dielectric composite layers deposited by sputtering without any intentional substrate heating. The films were deposited on glass and (100) crystalline silicon (c-Si) substrates from ceramic targets by using argon (At) and oxygen (O(2)) as sputtering and reactive gases, respectively. The incorporation Of SiO(2) and Al(2)O(3) into hafnia was obtained by co-sputtering and it was controlled by adjusting the ratio of r.f. power applied between the targets. The HfO(2) films present a microcrystalline structure, when deposited at room temperature (RT). The lowest leakage current in c-Si MIS (Metal-Insulator-Semiconductor) structures (below 10(9) A/cm(2) at 10 V on films with a thickness around 180 nm) was obtained for an Ar/O(2) ratio of 14:1 sccm, and further increase in O(2) flow does not enhance the electrical characteristics. The co-deposition Of SiO(2) or Al(2)O(3) with hafnia has a strong influence on the structure of the resulting films since they become amorphous. The leakage current in MIS structures incorporating these multi-component dielectrics is reduced at least by a factor of 2, which is accompanied by an increase on the band gap. The dielectric constant is decreased due to the lower values for SiO(2) and Al(2)O(3)
Original languageUnknown
Pages (from-to)2149-2154
JournalPhysica Status Solidi A-Applications And Materials Science
Volume206
Issue number9
DOIs
Publication statusPublished - 1 Jan 2009

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