The structural and electrical characterization of a HfErOx dielectric for MIM capacitor DRAM applications

Hafnium erbium oxide (HfErOx) thin films were formed using atomic layer deposition. The effect of using different Hf:Er pulse ratios on the electrical and structural properties of the HfErOx thin films (∼9 nm) in metal–insulator–metal (MIM) capacitor structures have been investigated and comparisons made between as-deposited and annealed samples. We report the stabilisation of the higher dielectric constant (k) tetragonal/cubic phase by optimising the Hf:Er pulse ratio. The dielectric properties post thermal anneal at 500 °C were studied. A leakage current in the order of ∼1 × 10−8 (A/cm2) at a voltage of 1 V and a capacitance equivalent thickness of ∼1.4 nm have been achieved post thermal annealing at 500 °C.

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