Impact of Chamber/Annealing Temperature on the Endurance Characteristic of Zr:HfO2 Ferroelectric Capacitor

Abstract

The endurance characteristic of Zr-doped HfO2 (HZO)-based metal–ferroelectric–metal (MFM) capacitors fabricated under various deposition/annealing temperatures in the atomic layer deposition (ALD) process was investigated. The chamber temperature in the ALD process was set to 120 °C, 200 °C, or 250 °C, and the annealing temperature was set to 400 °C, 500 °C, 600 °C, or 700 °C. For the given annealing temperature of 700 °C, the remnant polarization (2Pr) was 17.21 µC/cm2, 26.37 µC/cm2, and 31.8 µC/cm2 at the chamber temperatures of 120 °C, 200 °C, and 250 °C, respectively. For the given/identical annealing temperature, the largest remnant polarization (Pr) was achieved when using the chamber temperature of 250 °C. At a higher annealing temperature, the grain size in the HZO layer becomes smaller, and thereby, it enables to boost up Pr. It was observed that the endurance characteristics for the capacitors fabricated under various annealing/chamber temperatures were quite different. The different endurance characteristics are due to the oxygen and oxygen vacancies in ferroelectric films, which affects the wakeup/fatigue behaviors. However, in common, all the capacitors showed no breakdown for an externally applied pulse (up to 108 cycles of the pulse).

Combined effects of the deposition temperature and metal electrodes on ferroelectric properties of atomic-layer-deposited Hf0.5Zr0.5O2 films

“…The extracted parameters regarding ferroelectric properties are summarized in table S1. As shown in figures 1(a)-(d), the increase in T dep causes the polarization characteristics to change from antiferroelectric to ferroelectric, and this trend agrees with the previously reported results using TiN electrodes [7][8][9]. However, the transition temperatures (corresponding to T dep ) of the capacitors with TiN and Mo electrodes are slightly different.…”

“…Among the various process parameters required for the demonstration of ferroelectricity in Hf 1−x Zr x O 2 films, the atomic layer deposition (ALD) temperature (T dep ) is significant [7][8][9] because it primarily determines the initial phase of the film before the post-metallization annealing (PMA) process. The single-layered HfO 2 and ZrO 2 films have identical polymorphisms after crystallization, that is, t-and m-phases, depending on the film thickness and T dep [10,11], although ZrO 2 is more prone to crystallization than HfO 2 [12].…”

“…Several studies have examined the ferroelectric properties of Hf 1−x Zr x O 2 films while independently varying the T dep of ALD [7][8][9] and metal electrodes [6,[15][16][17][18]; however, only few reports exist on the combined effects of both process parameters. This study examines the phase evolution and ferroelectric properties of the Hf 0.5 Zr 0.5 O 2 (HZO) films as a function of the T dep of ALD using two different metal electrodes, namely, TiN and Mo electrodes.…”

“…This study examines the phase evolution and ferroelectric properties of the Hf 0.5 Zr 0.5 O 2 (HZO) films as a function of the T dep of ALD using two different metal electrodes, namely, TiN and Mo electrodes. Although other parameters, such as film thickness [6,19,20] and annealing temperature [6,9,21], also have significant effects on the ferroelectric properties of the HZO films, they were fixed in this experiment. Effects of T dep on the polymorphism of the HZO film differed depending on the type of the electrode materials.…”

In search of Pca21 phase ferroelectrics

“…Hafnia-based ferroelectrics have become the ferroelectric material of choice at ∼10 nm thickness [5][6][7], which is significant for nonvolatile ferroelectric random access memory [8,9], ferroelectric field effect transistor [10,11] as well as negative capacitance transistor applications [12,13] at the nanoscale. In particular, HZO is even more promising due to its low processing temperature (400 • C-450 • C) [14][15][16][17]. Compared with traditional perovskite ferroelectrics such as Pb(Zr,Ti)O 3 (PZT) [18], the greatest benefit of HZO lies in that it can well maintain net spontaneous polarization even below 10 nm thickness [19] while in PZT the formation of 180 • domains tends to eliminate the net polarization [20].…”