Impact of interfaces on bipolar resistive switching behavior in amorphous Ge–Sb–Te thin films

Abstract

Electrochemical metallization memories have received much attention as candidates for next generation non-volatile memory applications, due to their fast switching speed, simple structure, high scalability and low energy consumption. Chalcogenide compounds like Ge–Sb–Te-based materials are extensively studied solid electrolytes for such devices and considered within the most promising candidates. In this work, the influence of different electrode materials on bipolar resistive switching characteristics of amorphous Ge–Sb–Te thin films with close composition to 2:2:5, prepared by pulsed laser deposition, is studied. Detailed investigations by current-voltage measurements, secondary ion mass spectrometry and cross-sectional transmission electron microscopy in conjunction with energy-dispersive x-ray spectroscopy are presented. Depending on the utilized electrode material, analog switching (Cu, Ag, Ti), digital switching (Co, Cr, Ta, Al) or no switching (Pt, Au and Cr-CrOx) occurs. This work shows that the switching behavior of Ge–Sb–Te strongly depends on the solubility and reactivity of the electrode material.

Epitaxial layered Sb2Te3 thin films for memory and neuromorphic applications

“…In the presented study, a slight expansion of c-lattice parameter is also perceived for the Sb 2 Te 3 thin film after Cu top electrode deposition (figure 7(b)), pointing also to a possible diffusion. Such diffusion effects of Ag and Cu are often found in amorphous chalcogenides compounds [52].…”

“…Ag/Sb 2 Te 3 /Si instead of Ag/Sb 2 Te 3 /Si/Au). Just before deposition of top electrodes, the samples were dipped in de-ionized water for one minute in order to remove the surface oxide layer on the Sb 2 Te 3 , formed by oxidation in air [51,52]. The successful removal of surface oxide was confirmed in an additional performed XPS measurement.…”

“…Because memristive properties are strongly influenced by reaction layer formation or diffusion from electrode materials into the working layer [52], it is important to assess the impact of electrode metals on the microstructure of the devices. Figure 7(a) displays the Sb 2 Te 3 (00015) reflection before and after the deposition of Ag top electrodes.…”

“…By utilizing more reactive Cr and Ti electrode layers, a small hysteresis in I-V curves without previous electroforming step occurs (figures S4(c) and (d), respectively). It can be assumed that a reaction layer has formed at the metal/chalcogenide interface [52]. The slight modulation of resistance may originate from trapping/detrapping effects [10] or migration of vacancies that are generated due to the reaction layer [49].…”

High-performance artificial neurons based on Ag/MXene/GST/Pt threshold switching memristors

“…Therefore, the different GST-based ECM devices arising from its unique electrical and optical characteristics are recently designed for the reconfigurable and brain-inspired system applications. [21][22][23][24][25][26][27] However, the possibility of applying the GST-based TS memristor to artificial neurons is yet to be reported. In this article, we strategically prepare an Ag/MXene/GST/Pt memristor by inserting a 2D material MXene (Ti 3 C 2 ) into the Ag/GST/Pt device to reduce the power consumption.…”