Comparison of sputtering and atomic layer deposition based ultra-thin alumina protective layers for high temperature surface acoustic wave devices

Miling Zhang; Jinkai Chen; Weipeng Xuan; Xinyu Song; Hongsheng Xu; Jikai Zhang; Jian Wu; Hao Jin; Shurong Dong; Jikui Luo

Journal of Materials Research and Technology (Nov 2021)

Comparison of sputtering and atomic layer deposition based ultra-thin alumina protective layers for high temperature surface acoustic wave devices

Miling Zhang,
Jinkai Chen,
Weipeng Xuan,
Xinyu Song,
Hongsheng Xu,
Jikai Zhang,
Jian Wu,
Hao Jin,
Shurong Dong,
Jikui Luo

Affiliations

Miling Zhang: Ministry of Education, Key Laboratory of RF Circuits and Systems, Hangzhou Dianzi University, Hangzhou, 310018, China
Jinkai Chen: Ministry of Education, Key Laboratory of RF Circuits and Systems, Hangzhou Dianzi University, Hangzhou, 310018, China; Corresponding author.
Weipeng Xuan: Ministry of Education, Key Laboratory of RF Circuits and Systems, Hangzhou Dianzi University, Hangzhou, 310018, China
Xinyu Song: Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang, College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, China
Hongsheng Xu: Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang, College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, China; Key Laboratory of Intelligent Computing and Signal Processing of Ministry of Education, School of Electronics and Information Engineering, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China
Jikai Zhang: Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang, College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, China
Jian Wu: Ministry of Education, Key Laboratory of RF Circuits and Systems, Hangzhou Dianzi University, Hangzhou, 310018, China
Hao Jin: Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang, College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, China; ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, 311200, China
Shurong Dong: Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang, College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, China; ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, 311200, China
Jikui Luo: Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang, College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, China; ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, 311200, China; Corresponding author.

Journal volume & issue: Vol. 15
pp. 4714 – 4724

Abstract

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Surface acoustic wave (SAW) can be used as passive wireless sensors in high temperature environments. For such applications, protective layers are crucial and important for the SAW sensors. In this paper, ultra-thin Al2O3 layers prepared by atomic layer deposition (ALD) and RF magnetron sputtering were used to protect SAW devices with platinum (Pt) electrodes and their temperature stability was studied systematically. The devices were thermally treated up to 1150 °C in air, the real-time resistance of Pt resistive tracks with a sputtering Al2O3 protective layer showed much better and improved thermal stability than those without or with an ALD Al2O3 protective layer. Microstructure characterizations showed that the superior temperature stability is attributed to its mixture of amorphous and nano-crystalline nature of the Al2O3 layer deposited by sputtering and full recrystallization at high temperatures. SAW devices with a sputtering Al2O3 protective layer after 1150 °C treatment maintained almost unchanged properties, while those with an ALD Al2O3 protective layer failed to work. Investigation also indicated there exists an optimal thickness for the sputtering Al2O3 layer to achieve best performance and thermal-stability for the SAW devices. Besides, the deposition rate of Al2O3 layer by sputtering is 10 times faster than that by ALD. All the results demonstrate that the sputtering Al2O3 protective layer is more suitable for high temperature SAW device applications owing to its lower cost, higher deposition rate and temperature stability.

Published in Journal of Materials Research and Technology

ISSN: 2238-7854 (Print); 2214-0697 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Technology: Mining engineering. Metallurgy
Website: https://www.journals.elsevier.com/journal-of-materials-research-and-technology/

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