Temperature-resilient solid-state organic artificial synapses for neuromorphic computing

Abstract

<jats:p>Devices with tunable resistance are highly sought after for neuromorphic computing. Conventional resistive memories, however, suffer from nonlinear and asymmetric resistance tuning and excessive write noise, degrading artificial neural network (ANN) accelerator performance. Emerging electrochemical random-access memories (ECRAMs) display write linearity, which enables substantially faster ANN training by array programing in parallel. However, state-of-the-art ECRAMs have not yet demonstrated stable and efficient operation at temperatures required for packaged electronic devices (~90°C). Here, we show that (semi)conducting polymers combined with ion gel electrolyte films enable solid-state ECRAMs with stable and nearly temperature-independent operation up to 90°C. These ECRAMs show linear resistance tuning over a &gt;2× dynamic range, 20-nanosecond switching, submicrosecond write-read cycling, low noise, and low-voltage (±1 volt) and low-energy (~80 femtojoules per write) operation combined with excellent endurance (&gt;10<jats:sup>9</jats:sup> write-read operations at 90°C). Demonstration of these high-performance ECRAMs is a fundamental step toward their implementation in hardware ANNs.</jats:p>

Contact Modulated Ionic Transfer Doping in All‐Solid‐State Organic Electrochemical Transistor for Ultra‐High Sensitive Tactile Perception at Low Operating Voltage

“…This also correlates well with a recent report which shows temperature-resilient behavior in solid-state OECTs. [47] Furthermore, the devices operate well after multiple lamination and delamination processes, which therefore allow reuse ( Figure S8, Supporting Information).…”

Filament‐Free Bulk Resistive Memory Enables Deterministic Analogue Switching

“…Moreover, switching is linear and symmetric, essential attributes required to achieve high network training accuracy: [ 1,34,36 ] Crossbar simulations (Cross‐Sim [ 36 ] ) show ≈97% training accuracy for the MNIST training set (Figure S6, Supporting Information). While this device is a type of electrochemical random‐access memory (ECRAM), [ 40–50 ] the bulk‐RRAM cells based on oxygen vacancies presented here provide significant advantages in terms of scalability, retention, and CMOS compatibility over previously developed ECRAM, and will be discussed later.…”

“…This contrasts strongly with other types of ECRAM cells, which also have three terminals but that need electronic switches to isolate the gate from the channel. [ 40–50 ] We plot the memory loss over time ( Figure a) when shorting the base and switching layers after setting the device to a high‐conductance state. The switching layer decay time strongly depends on temperature: at room temperature, it decays less than 0.3% after one week.…”

“…Whereas bulk‐RRAM cells retain state by immobilizing and blocking ion migration, ECRAM cells that operate at constant temperature instead use electronic switches to block electron migration between the gate and channel. [ 40–50 ] This method does not scale well for smaller devices: R OFF is constant and depends on the properties of the switch while C decreases proportionally with the area (Figure 4e). Assuming that R OFF ≈ 10 13 Ω (ref.…”

“…Another class of analogue memory with significant recent research is ECRAM [ 40–50 ] based on bulk transport of Li + or H + defects. Our statistical ensemble analysis also explains why these ECRAM switch more linearly and deterministically than filamentary devices.…”