Restricted use of hazardous environmental chemicals is one important challenge that the semiconductor industry needs to face to improve its sustainability.Ovonic threshold switching(OTS)ternary compound materials used...Restricted use of hazardous environmental chemicals is one important challenge that the semiconductor industry needs to face to improve its sustainability.Ovonic threshold switching(OTS)ternary compound materials used in memory selector devices contain As and Se.Engineering these elements out of these materials requires significant research effort.To facilitate this process,we performed systematic material screening for As/Se-free ternary materials,based on ab-initio simulations.To limit the large amount of possible chemical compositions to fewer promising candidates,we used physics-based material parameter filters like material stability,electronic properties,or change in polarizability.The OTS gauge concept is introduced as a computed parameter to estimate the probability of a material to show an OTS behavior.As a result,we identified 35 As/Se-free ternary alloy compositions for stand-alone OTS memory applications,as well as 12 compositions for RRAM selector applications.This work aims seeding the development of As/Se-free OTS materials.展开更多
Nonvolatile memory devices based on filamentary resistance switching （KS） are among the frontrunners to fuel future devices and sensors of the internet of things （IoT） era. The capability of many two distinctive r...Nonvolatile memory devices based on filamentary resistance switching （KS） are among the frontrunners to fuel future devices and sensors of the internet of things （IoT） era. The capability of many two distinctive resistive states in response to an external electrical stimulus has been demonstrated. Through years of selection, cells based on the drift of metal ions, namely conductive-bridge memory devices, have shown a wide range of applications with nanosecond switching speeds, nanometer scalability, high-density, and low power-consumption. However, for low （sub-10-~A） current operation, a critical challenge is still represented by programming variability and by the stability of the conductive filament over time. Here, by introducing the concept of reverse filament growth （RFG）, we managed to control the structural reconfiguration of the conductive filament inside a memory cell with significant enhancements of each of the aforementioned properties. A first-in-class Cu-based switching device is demonstrated, with a dedicated stack that enabled us to systematically trigger RFG, thus tuning the device＇s properties. Along with nanosecond switching speeds, we achieved an endurance of up to 106 cycles with a 102 read window, with outstanding disturb immunity and optimal stability of the filament over time. Furthermore, by tuning the filament＇s shape, an excellent control of multi-level bit operations was achieved. Thus, this device offers high flexibility in memory applications.展开更多
基金This work was carried out in the framework of the imec Core CMOS-Active Memory Program.T.R.acknowledges the support by Research Foundation-Flanders(FWO)for providing the funding via strategic basic research PhD fellowship(grant no.1SD4721).
文摘Restricted use of hazardous environmental chemicals is one important challenge that the semiconductor industry needs to face to improve its sustainability.Ovonic threshold switching(OTS)ternary compound materials used in memory selector devices contain As and Se.Engineering these elements out of these materials requires significant research effort.To facilitate this process,we performed systematic material screening for As/Se-free ternary materials,based on ab-initio simulations.To limit the large amount of possible chemical compositions to fewer promising candidates,we used physics-based material parameter filters like material stability,electronic properties,or change in polarizability.The OTS gauge concept is introduced as a computed parameter to estimate the probability of a material to show an OTS behavior.As a result,we identified 35 As/Se-free ternary alloy compositions for stand-alone OTS memory applications,as well as 12 compositions for RRAM selector applications.This work aims seeding the development of As/Se-free OTS materials.
文摘Nonvolatile memory devices based on filamentary resistance switching （KS） are among the frontrunners to fuel future devices and sensors of the internet of things （IoT） era. The capability of many two distinctive resistive states in response to an external electrical stimulus has been demonstrated. Through years of selection, cells based on the drift of metal ions, namely conductive-bridge memory devices, have shown a wide range of applications with nanosecond switching speeds, nanometer scalability, high-density, and low power-consumption. However, for low （sub-10-~A） current operation, a critical challenge is still represented by programming variability and by the stability of the conductive filament over time. Here, by introducing the concept of reverse filament growth （RFG）, we managed to control the structural reconfiguration of the conductive filament inside a memory cell with significant enhancements of each of the aforementioned properties. A first-in-class Cu-based switching device is demonstrated, with a dedicated stack that enabled us to systematically trigger RFG, thus tuning the device＇s properties. Along with nanosecond switching speeds, we achieved an endurance of up to 106 cycles with a 102 read window, with outstanding disturb immunity and optimal stability of the filament over time. Furthermore, by tuning the filament＇s shape, an excellent control of multi-level bit operations was achieved. Thus, this device offers high flexibility in memory applications.
