Write-Once-Read-Many-Times Nonvolatile Memory Characteristics of Sol–Gel Hafnium Zirconium Oxide

In this article, write-once-read-many-times (WORM) memory behavior of HfZrO (HZO) ferroelectric material is demonstrated. A stoichiometric Hf $_{\text{0}.\text{5}}$ Zr $_{\text{0}.\text{5}}$ O $_{\text{2}}$ thin film prepared using a sol–gel process is used as a resistive switching (RS) layer. The top and bottom electrodes are Al and n $^{+}$ -Si, respectively. The Al/HZO/n $^{+}$ -Si memory shows a low current of 10 $^{-\text{11}}$ A at a read voltage of 0.6 V in the OFF state. A writing process occurs when the voltage on Al electrode increases to $\sim$ 2.8 V. The ratio of the OFF-state resistance ( $\textit{R}_{\text{off}}\text{)}$ to ON-state resistance ( $\textit{R}_{\text{on}}\text{)}$ is 10 $^{\text{6}}$ . Both data retention and stress tests indicate that $\textit{R}_{\text{off}}$ and $\textit{R}_{\text{on}}$ can remain the same for over 10 $^{\text{4}}$ s. Moreover, data stability is further confirmed at an elevated temperature of 85 $^{\circ}$ C. The switching speed of the HZO memory is $\sim$ 40 ns, corresponding to a power consumption of 0.98 nJ. The RS mechanism is investigated, and the carrier conduction mechanisms are studied by the analysis of current–voltage characteristics at different temperatures.