中国物理B ›› 2012, Vol. 21 ›› Issue (10): 106801-106801.doi: 10.1088/1674-1056/21/10/106801

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

Tunable Ba0.5Sr0.5TiO3 film bulk acoustic resonators using SiO2/Mo Bragg reflectors

杨天应, 蒋书文, 李汝冠, 姜斌   

  1. State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
  • 收稿日期:2012-03-04 修回日期:2012-04-28 出版日期:2012-09-01 发布日期:2012-09-01
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 60871049 and 50972024).

Tunable Ba0.5Sr0.5TiO3 film bulk acoustic resonators using SiO2/Mo Bragg reflectors

Yang Tian-Ying (杨天应), Jiang Shu-Wen (蒋书文), Li Ru-Guan (李汝冠), Jiang Bin (姜斌)   

  1. State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
  • Received:2012-03-04 Revised:2012-04-28 Online:2012-09-01 Published:2012-09-01
  • Contact: Yang Tian-Ying, Jiang Shu-Wen E-mail:yangtianying521@163.com; jiangsw@uestc.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 60871049 and 50972024).

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摘要： Tunable and switchable Ba0.5Sr0.5TiO3 film bulk acoustic resonators (FBARs) based on SiO2/Mo Bragg reflectors are explored, which can withstand high temperature for the deposition of BaxSr1-xTiO3 (BST) films at 800 ℃. The dc bias-dependent resonance may be attributed to the piezoelectricity of the BST film induced by an electrostrictive effect. The series resonant frequency is strongly dc bias-dependent and shifts downwards with dc bias increasing, while the parallel resonant frequency is only weakly dc bias-dependent and slightly shifts upwards at low dc bias (< 45 V) while downwards at higher dc bias. The calculated relative tunability of shifts at series resonance frequency is around -2.3% and the electromechanical coupling coefficient is up to approximately 8.09% at 60-V dc bias, which can be comparable to AlN FBARs. This suggests that a high-quality tunable BST FBAR device can be achieved through the use of molybdenum (Mo) as the high acoustic impedance layer in a Bragg reflector, which not only provides excellent acoustic isolation from the substrate, but also improves the crystallinity of BST films withstanding higher deposition temperature.

关键词: BaxSr1-xTiO3, tunable film bulk acoustic wave resonator, ferroelectric, acoustic Bragg reflector

Abstract: Tunable and switchable Ba0.5Sr0.5TiO3 film bulk acoustic resonators (FBARs) based on SiO2/Mo Bragg reflectors are explored, which can withstand high temperature for the deposition of BaxSr1-xTiO3 (BST) films at 800 ℃. The dc bias-dependent resonance may be attributed to the piezoelectricity of the BST film induced by an electrostrictive effect. The series resonant frequency is strongly dc bias-dependent and shifts downwards with dc bias increasing, while the parallel resonant frequency is only weakly dc bias-dependent and slightly shifts upwards at low dc bias (< 45 V) while downwards at higher dc bias. The calculated relative tunability of shifts at series resonance frequency is around -2.3% and the electromechanical coupling coefficient is up to approximately 8.09% at 60-V dc bias, which can be comparable to AlN FBARs. This suggests that a high-quality tunable BST FBAR device can be achieved through the use of molybdenum (Mo) as the high acoustic impedance layer in a Bragg reflector, which not only provides excellent acoustic isolation from the substrate, but also improves the crystallinity of BST films withstanding higher deposition temperature.

Key words: BaxSr1-xTiO3, tunable film bulk acoustic wave resonator, ferroelectric, acoustic Bragg reflector

中图分类号:  (Mechanical and acoustical properties)

  • 68.60.Bs
72.50.+b (Acoustoelectric effects)