Sputtered multicomponent amorphous dielectrics for transparent electronics

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)