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 degrees 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 degrees 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 degrees C. In addition, compared to other tri-layer stacks, the stack deposited at 300 degrees C shows good conductivity. Therefore, compared to other samples, the tri-layer stack deposited at 300 degrees C has improved electrical characteristics. It is shown that the substrate temperature has a significant impact on the electrical properties of the stack.