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/sub 0.2/Sn/sub 0.2/Ti/sub 0.6/O₂ 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/μm². Breakdown fields were measured to be 3-5 MV/cm, yielding a figure of merit /spl epsi//spl epsi/₀E/sub br/=15-30 μC/cm², up to eightfold higher than conventional deposited SiO₂. Leakage currents, measured at 1.0 MV/cm, were in the range 10/sup -9/-10/sup -7/ A/cm². This material appears well-suited for use in Si-IC device technology, for example as storage capacitors in DRAM.