Potential of ITO thin film for electrical probe memory applications

Abstract

Electrical probe memory has received considerable attention during the last decade due to its prospective potential for the future mass storage device. However, the electrical probe device with conventional diamond-like carbon capping and bottom layers encounters with large interfacial contact resistance and difficulty to match the experimentally measured properties, while its analog with titanium nitride capping and bottom layers also faces serious heat dissipation through either probe and silicon substrate. Therefore, the feasibility of using indium tin oxide (ITO) media for the capping and bottom layers of the electrical probe device is investigated by tailoring the thickness and electrothermal properties of the ITO capping and bottom layers within experimentally established range and subsequently calculating the resultant temperature at several predefined points based on a previously developed three-dimensional model. To meet the required temperature and to fit the experimentally reported values, the thickness, electrical conductivity, and thermal conductivity of the ITO capping and bottom layers are found to be 5 nm, 103 Ω−1 m−1, 0.84 W m−1 K−1, and 200 nm, 1.25 × 106 Ω−1 m−1, 0.84 W m−1 K−1, respectively. The practicality of using this optimized device to achieve ultrahigh density, ultralow energy consumption, ultrafast switching speed, low interfacial contact resistance, and high thermal reliability has also been demonstrated.

Rapid thermal annealing for high-quality ITO thin films deposited by radio-frequency magnetron sputtering

“…ITO is an attractive material because it exhibits excellent properties as a transparent conductive oxide (TCO) material that can be tuned during deposition in order to obtain materials for specific applications [7,11]. Due to these features, ITO films are promising components for the development of high-performance optoelectronics [7,11–13] and photovoltaic devices. In order to use ITO thin films for photovoltaic applications, samples with reproducible properties are required [8,14].…”

Applications of Phase Change Materials in Electrical Regime From Conventional Storage Memory to Novel Neuromorphic Computing

“…As contact resistance is mainly determined by the electricial resistivities of probe and capping layer, it is timely to search for a thin capping layer that however allows for a high electrical conductivity and a low thermal conductivity. Triggered by above quest, two additional capping layers that are made of TiN [113], [114] and ITO medium [115] respectively, have most recently been proposed. As suggested from its bottom electrode application, TiN media enables a high electrical conductivity and a relatively low thermal conducitivity under a thickness of 2 nm, satisfying the above requirement.…”

“…As suggested from its bottom electrode application, TiN media enables a high electrical conductivity and a relatively low thermal conducitivity under a thickness of 2 nm, satisfying the above requirement. Similar to TiN, a 5 nm thick ITO layer also exhibits an electrical conductivity of 10 3 −1 m −1 and a thermal conductivity of 0.84 Wm −1 K −1 [115], consequently leading to a low contact resistance. Although both TiN and ITO capping layer provide satisfying write performance, their feasibility of inducing distinguishable readout signal remains questionable.…”

Recent Progress on Probe-Based Storage Devices

“…As a result, the electrical conductivity of the capping [58], [59]. (b) Reproduced with permission from [62], [64]. (c) Reproduced with permission from [66], [67].…”

“…layer needs to be further boomed to generate adequate joule heating for a low pulse. TiN and Indium Tin Oxide (ITO) with an electrical conductivity and a thermal conductivity of 1.25 × 10 6 −1 m −1 , and 4 Wm −1 K −1 , respectively, are two typical medium that satisfy above demand and the practicality of using these two medium for the capping layer of phase-change electrical probe memory has most recently been studied [62], [63], as shown in Figure 7(b). As revealed by Figure 7(b), due to their relatively high thermal conductivity, the maximal temperature inside the capping layer has been limited to 1000 • C and 850 • C for TiN and ITO capping, respectively, much lower than their melting point (i.e., ∼3200 • C for TiN and ∼1400 • C for ITO).…”