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

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 _0.2Sn _0.2Ti _0.6O 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/μm ². Breakdown fields were measured to be 3-5 MV/cm, yielding a figure of merit εε ₀E _br = 15-30 μC/cm ², up to eightfold higher than conventional deposited SiO ₂. Leakage currents, measured at 1.0 MV/cm, were in the range 10 ^-9-10 ^-7 A/cm ². This material appears well-suited for use in Si-IC device technology, for example as storage capacitors in DRAM.