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 Hf_xZr_1-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.