First Experimental Demonstration of Robust HZO/β-Ga₂O₃ Ferroelectric Field-Effect Transistors as Synaptic Devices for Artificial Intelligence Applications in a High-Temperature Environment
Jinhyun Noh, Hagyoul Bae, Junkang Li, Yandong Luo, Yiming Qu, Tae Joon Park, Mengwei Si, Xuegang Chen, Adam Charnas, Wonil Chung, Xiaochen Peng, Shriram Ramanathan, Shimeng Yu, Peide D. Ye
Abstract
We have experimentally demonstrated robust beta-gallium oxide ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) ferroelectric (FE) field-effect transistors (FeFETs) on a sapphire substrate operated up to 400 °C. Atomic layer deposited (ALD) Hf <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sub> Zr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> [hafnium zirconium oxide (HZO)] is used as the FE dielectric. The HZO/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> FeFETs are studied for their synaptic behavior applications at elevated temperatures. The devices show distinguishable polarization switching operation with the output conductance quasi-linearly controlled by the number of input pulses on the FE gate. In a simulation, on-chip learning accuracy reaches 94% at elevated temperatures using the Modified National Institute of Standards and Technology (MNIST) data set with a simple two-layer multilayer perceptron (MLP) network. These ultra wide bandgap semiconductor devices have the potential to fill the need for harsh environment neuromorphic applications.