Atomic Layer Deposition of ZrO₂ Films at High Temperatures (>350 °C) Using a Modified Cyclopentadienyl Zr Precursor

With tris(dimethylamino)cyclopentadienyl metal (CpX(NMe2)3) precursors, the optimum process temperature of atomic layer deposition (ALD) is higher for HfO2 films (∼350 °C) than ZrO2 films (∼320 °C). Since simultaneous ALD of the two films is required in HfxZr1–xO2 film processes, the optimum ALD temperatures of the two films need to be adjusted equally. The cyclopentadienyl Zr precursor (MCPZr) introduced in this study exhibits better thermal stability than that of CpZr(NMe2)3. ZrO2 films were grown using CpZr(NMe2)3 and MCPZr at 350 °C, the optimum ALD temperature of the HfO2 film using CpHf(NMe2)3, and the growth behavior and physicochemical and electrical properties were compared. The physical density was higher, and the impurity concentration was lower for the film grown using MCPZr compared to the film grown using CpZr(NMe2)3. The electrical properties of dielectric constant, leakage current, and dielectric breakdown also improved due to the improved physicochemical properties.