A Low-Leakage Zinc Oxide Transistor by Atomic Layer Deposition
Zhiyu Lin, Ziheng Wang, Jinxiu Zhao, Xiuyan Li, Mengwei Si
Abstract
In this work, we report an atomic layer deposited (ALD) zinc oxide (ZnO) transistor with low off-state leakage current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{I}_{ \mathrm{\scriptscriptstyle OFF}}$ </tex-math></inline-formula> ) ~ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${3} \times {10}^{-{18}}$ </tex-math></inline-formula> A/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> at high temperatures up to 147 °C, measured by devices with interdigitated electrodes with a wide channel width ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{W}_{\text {ch}}{)}$ </tex-math></inline-formula> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10000~\mu \text{m}$ </tex-math></inline-formula> , where the low <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{I}_{ \mathrm{\scriptscriptstyle OFF}}$ </tex-math></inline-formula> is still under the detection limit. The impact of ALD growth temperature and annealing on the electrical performance is systematically studied. It is found that low temperature deposition and post deposition annealing are effective to enhance the performance of the ALD ZnO transistors. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu _{\text {FE}}$ </tex-math></inline-formula> as high as 32.8 cm2/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}\cdot \text{s}$ </tex-math></inline-formula> , on/off ratio ~ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{12}}$ </tex-math></inline-formula> and subthreshold slope (SS) down to 75.3 mV/dec at room temperature are achieved. These results suggest ALD ZnO is a promising channel material for low off-state leakage current device applications.