Deposition of uniform Zr-Sn-Ti-O films by on-axis reactive sputtering

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Abstract
We describe the deposition of amorphous Zr-Sn-Ti-O (aZTT) dielectric thin films using conventional on-axis reactive sputtering. Thin films of composition Zr/sub 0.2/Sn/sub 0.2/Ti/sub 0.6/O/sub 2/ have excellent dielectric properties: 40-50-nm thick films with a dielectric constant of 50-70 were obtained, depending on the processing conditions, yielding a specific capacitance of 9-17 fF//spl mu/m/sup 2/. Breakdown fields were measured to be 3-5 MV/cm, yielding a figure of merit /spl epsi//spl epsi//sub 0/E/sub br/=15-30 /spl mu/C/cm/sup 2/, up to eightfold higher than conventional deposited SiO/sub 2/. Leakage currents, measured at 1.0 MV/cm, were in the range 10/sup -9/-10/sup -7/ A/cm/sup 2/. This material appears well-suited for use in Si-IC device technology, for example as storage capacitors in DRAM.