Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, California 92093, United States.
Material Science and Engineering Program, University of California San Diego, La Jolla, California 92093, United States.
ACS Appl Mater Interfaces. 2022 May 18;14(19):22252-22262. doi: 10.1021/acsami.1c24327. Epub 2022 May 6.
A gate-tunable synaptic device controlling dynamically reconfigurable excitatory and inhibitory synaptic responses, which can emulate the fundamental synaptic responses for developing diverse functionalities of the biological nervous system, was developed using ambipolar oxide semiconductor thin-film transistors (TFTs). Since the balanced ambipolarity is significant, a boron-incorporated SnO (SnO:B) oxide semiconductor channel was newly developed to improve the ambipolar charge transports by reducing the subgap defect density, which was reduced to less than 10 cm. The ambipolar SnO:B-TFT could be fabricated with a good reproductivity at the maximum process temperature of 250 °C and exhibited good TFT performances, such as a nearly zero switching voltage, the saturation mobility of ∼1.3 cm V s, -value of ∼1.1 V decade, and an on/off-current ratio of ∼8 × 10 for the p-channel mode, while ∼0.14 cm V s, ∼2.2 V decadeand ∼1 × 10 for n-channel modes, respectively. The ambipolar device imitated potentiation/depression behaviors in both excitatory and inhibitory synaptic responses by using the p- and n-channel transports by tuning a gate bias. The low-power consumptions of <20 and <2 nJ per pulse for the excitatory and inhibitory operations, respectively, were also achieved. The presented device operated under an ambient atmosphere and confirmed a good operation reliability over 5000 pulses and a long-term air environmental stability. The study presents the high potential of an ambipolar oxide-TFT-based synaptic device with a good manufacturability to develop emerging neuromorphic perception and computing hardware for next-generation artificial intelligence systems.
一种栅极可调谐突触器件，可动态控制可重构的兴奋性和抑制性突触响应，可模拟生物神经系统的基本突触响应，从而开发出各种功能，该器件使用双极型氧化物半导体薄膜晶体管（TFT）制成。由于双极性至关重要，因此新开发了掺硼的 SnO（SnO：B）氧化物半导体沟道，通过降低亚带隙缺陷密度来改善双极电荷输运，将亚带隙缺陷密度降低到小于 10 cm。双极 SnO：B-TFT 可以在最高工艺温度为 250°C 的条件下以良好的重现性进行制造，并且表现出良好的 TFT 性能，例如接近零的开关电压，饱和迁移率约为 1.3 cm V s，-值约为 1.1 V 十年，p 通道模式的导通/关断电流比约为 8×10，而 n 通道模式的分别约为 0.14 cm V s，约 2.2 V 十年和约 1×10。通过调节栅极偏压，双极器件可通过 p 型和 n 型传输来模拟兴奋性和抑制性突触响应中的增强/抑制行为。分别实现了兴奋性和抑制性操作的低功耗<20 和<2 nJ 脉冲。该器件在环境气氛下运行，并确认在 5000 多个脉冲以上具有良好的运行可靠性和长期的空气环境稳定性。该研究展示了具有良好制造性的双极氧化物-TFT 基突触器件在开发新兴的神经形态感知和计算硬件方面的巨大潜力，为下一代人工智能系统提供支持。
