Electrical Response of Al Based Zr-Doped Stacked Tri-Layer HfO2 Deposited at Various Substrate Temperature

This study examines how the substrate temperature affects the electrical characteristics of the Zr-doped HfO₂/Al/Zr-doped HfO₂ (HZO/Al/HZO) tri-layer stack. Tri-layer stack is deposited by a simultaneous use of RF magnetron sputtering for HfO₂ and DC magnetron sputtering for Zr and Al targets. During deposition, the substrate temperature is varied from 25 to 300°C. The observed hysteresis loop is prominent for the stack deposited at room temperature, while it becomes minute at higher temperatures. Interface trap density and oxide charge density of the tri-layer stack are minimum at 300°C and maximum at room temperatures. Frequency dispersion is detected in the stack deposited at room temperature, but it disappears in stacks deposited at 300°C. In addition, compared to other tri-layer stacks, the stack deposited at 300°C shows good conductivity. Therefore, compared to other samples, the tri-layer stack deposited at 300°C has improved electrical characteristics. It is shown that the substrate temperature has a significant impact on the electrical properties of the stack.