Electrical evidence of unstable anodic interface in Ru∕HfOx∕TiN unipolar resistive memory

Abstract

Unipolar resistive switching behaviors of Ru∕HfOx∕TiN devices with Ru as anode were investigated. Wide dispersion of switching operation parameters was observed. The conduction mechanisms in low and high resistance states of the devices were characterized to be Ohmic-like and tunneling, respectively. The band offset of the Ru∕HfOx interface was extracted from the measured tunneling current versus voltage characteristics. Instability of the band offset at the anodic interface was observed and may be responsible for the wide fluctuation of the operation voltage in the Ru∕HfOx∕TiN device at a high resistance state. The possible mechanism for these unstable characteristics of band offset at the Ru∕HfOx interface is also discussed.

Resistance switching in HfO2 metal-insulator-metal devices

“…1. As opposed to previous works, 7,9,10 it is also noticeable that the present films do not require a forming step. Ten successive cycles are shown in Fig.…”

Stabilizing electric switching of ferromagnetism in In2O3:Cu thin films

“…Resistance random access memory (RRAM) has attracted considerable interest due to its advantages of simple structure, low energy consumption, higher operating speed and higher endurance [16]. Oxide-Based RRAM devices has been reported by C. Walczyk et al [17], and the temperature-dependent IeV characteristics in fresh devices were attributed to the PooleeFrenkel mechanism with an extracted trap energy level below the HfO 2 conduction band.…”

Effects of O<formula formulatype="inline"><tex Notation="TeX">$_{\bf 2}$</tex></formula>/Ar Ratio and Growth Temperature on Resistive Switching Characteristics of Al/HfO<formula formulatype="inline"><tex Notation="TeX">$_{\bm x}$</tex> </formula>/ITO Memory Devices

“…Also, the oxygen vacancies and bulk crystallization of HfO 2 appear as a significant parameter as well, and the switching effect was considered to be caused due to the migration of oxygen vacancies along grain boundaries [15]- [18]. HfO 2 thin films were reported to be unipolar [18]- [20], bipolar [21], both unipolar and bipolar [22], or changing from unipolar to bipolar after oxygen annealing [23]. These reviews indicate that more studies are needed to understand RS in HfO 2 .…”