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Microwave tunable devices are critical components in phased array antennas and RF front-ends, and essential for the precisely control of frequency, phase and amplitude. Although bulk dielectric ceramic materials are widely used in these devices, they pose challenges for integration. In contrast, dielectric thin films offer significant advantages, including ease of integration, low cost, high tuning speed, low power consumption, compact size and continuous tunability, making them more compatible with modern integrated circuit fabrication processes. Currently, a key prerequisite for designing devices based on dielectric thin films is the use of low-permittivity, low-loss substrates to mitigate their impact on the overall dielectric performance, while simultaneously enhancing the crystalline quality of the films themselves. However, suitable substrates for epitaxial growth, such as MgO and Si, exhibit a significant lattice mismatch (>5%) with dielectric thin films. This poses a substantial challenge to achieving high-quality epitaxial growth, making it difficult to obtain dielectric thin films with both high tunability and low loss.
To address this challenge, we employed Pulsed Laser Deposition (PLD) to provide high-energy, non-equilibrium growth conditions. Through the precise control of parameters such as substrate temperature and growth oxygen pressure, we identified a suitable growth window that induces the Domain Matching Epitaxy (DME) mechanism which effectively accommodates the mismatch strain, enabling the successful fabrication of high-performance Ba0.6Sr0.4TiO3 (BSTO) epitaxial thin films on MgO(001) substrates. To investigate the effect of substrate temperature on the properties of the BSTO thin films, a series of films were prepared on MgO(001) substrates at temperatures of 680 ℃, 700 ℃, 730 ℃, 760 ℃ and 780 ℃, while other growth conditions were held constant. The study reveals that as the substrate temperature increases, the crystallinity, tunability, and figure of merit (FOM) of the films are significantly improved. The film grown at 780 ℃ exhibited a high tunability of 67.2%, a quality (Q) factor of 49, and a FOM of 32.93. Compared to previously reported results, the Ba0.6Sr0.4TiO3 thin films prepared in this study demonstrate superior dielectric tunability and lower dielectric loss.
To explore the thermal stability of the Ba0.6Sr0.4TiO3 thin film, its performance was characterized using Raman spectroscopy and Capacitance-Voltage measurements over a temperature range of 25 ℃ to 225 ℃. Raman spectra indicated that the lattice vibrational modes of the Ba0.6Sr0.4TiO3 film changed with increasing temperature. Between 175 ℃ and 225 ℃, the film completely transformed from the tetragonal phase to the Raman-inactive cubic phase. Concurrently, the nonlinear "butterfly" characteristic of the C-V curves vanished due to the disappearance of ferroelectric domains. The dielectric constant and tunability reached their maximum values at approximately 60 ℃ before decreasing, whereas the Q-factor peaked at around 205 ℃. The motion of domain walls within the film is constrained not only by internal stress fields and defects but also by strong pinning effects at the film-substrate interface and the free surface of the film. This research systematically analyzes the influence of factors such as surface morphology, crystal structure, and temperature on the dielectric properties of Ba0.6Sr0.4TiO3 epitaxial thin films. It lays a foundation for elucidating the broadband structure-property relationships in Ba1-xSrxTiO3 thin films and highlights their significant potential for applications in tunable microwave devices.-
Keywords:
- Ferroelectric materials /
- Strontium barium titanate /
- Growth regulation /
- Dielectric properties
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[1] Emadi F, Nemati A, Hinterstein M, Adabiroozjaei E 2019 Ceram. Int. 45 5503
[2] Borderon C, Ginestar S, Gundel H W, Haskou A, Nadaud K, Renoud R, Sharaiha A 2020 IEEE Trans. Ultrason. Ferroelectr. Freq. Control. 67 1733
[3] Ma H, Lou J, Wang J, Dong B W, Feng M D, Li Z Q, Qu S B 2019 J. Air Force Eng. Univ. 20 53 (in Chinese) [马华，娄菁，王军，董博文，冯明德，李智强，屈绍波 2019 空军工程大学学报 20 53]
[4] Johnson K M 1962 J. Appl. Phys. 33 2826
[5] Dong H T, Jian J, Li H F, Jin D R, Chen J G, Cheng J R 2017 J. Alloys Compd. 725 54
[6] Bayrak T, Ozgit-Akgun C, Goldenberg E 2017 J. Non-Cryst. Solids 475 76
[7] Subramanyam G, Cole M W, Sun N X, Kalkur T S, Sbrockey N M, Tompa G S, Guo X M, Chen C L, Alpay S P, Rossetti G A Jr, Dayal K, Chen L Q, Schlom D G 2013 J. Appl. Phys. 114 191301
[8] Liu H G, Avrutin V, Zhu C Y, Özgür Ü, Yang J, Lu C Z, Morkoç H 2013 J. Appl. Phys. 113 044108
[9] Luo W, Chen X, Fan J, Hu Y, Zheng Z, Fu Q 2016 Ceram. Int. 42 17229
[10] Jiao T J, You C, Tian N, Ma L, Duan Z F, Yan F X, Ren P R, Zhao G Y 2022 Appl. Surf. Sci. 590 153112
[11] Wang J, Zhang T, Xia H, Xiang J, Li W, Duo S 2008 J. Sol-Gel Sci. Technol. 47 102
[12] Wander A, Bush I J, Harrison N M 2003 Phys. Rev. B 68 233405
[13] Misirlioglu I B, Alpay S P, He F, Wells B O 2006 J. Appl. Phys. 99 104103
[14] Peng L S J, Xi X X, Moeckly B H, Alpay S P 2003 Appl. Phys. Lett. 83 4592
[15] Tagantsev A K, Sherman V O, Astafev K F, Venkatesh J, Setter N 2003 J. Electroceram. 11 5
[16] Acikel B 2002 High Performance Barium Strontium Titanate Varactor Technology for Low Cost Circuit Applications Ph.D. Dissertation (Santa Barbara: University of California)
[17] Su H T, Lancaster M J, Huang F, Wellhofer F 2000 Microwave Opt. Technol. Lett. 24 155
[18] Gao L, Guan Z, Huang S, Liang K, Chen H, Zhang J 2019 J. Mater. Sci.: Mater. Electron. 30 12821
[19] J. Schultheiß, H. Kungl, J. Koruza 2019 J. Appl. Phys. 125 174101
[20] Damjanovic D 1998 Rep. Prog. Phys. 61 1267
[21] Xiong P Y, Ni Z, Lin Z F, Bai X B, Liu T X, Zhang X Y, Yuan J, Wang X, Shi J, Jin K 2023 Acta Phys. Sin. 72 097701 (in Chinese)[熊沛雨, 倪壮, 林泽丰, 柏欣博, 刘天想, 张翔宇, 袁洁, 王旭, 石兢, 金魁 2023 物理学报 72 097701]
[22] Shen D K, Yang Z H, Guo P Y, Zhao M L, Ge J, Deng G X, Wang A J 2024 J. Chin. Ceram. Soc. 52 229 (in Chinese)[沈德坤, 杨淄涵, 郭沛源, 赵梦玲, 葛健, 邓功勋, 王爱记 2024 硅酸盐学报 52 229]
[23] Kim H S, Kim H G, Kim I D, Kim K B, Lee J C 2005 Appl. Phys. Lett. 87 212903
[24] Zhang J, Zhai J, Chou X, Shao J, Lu X, Yao X 2009 Acta Mater. 57 4491
[25] Chung U, Elissalde C, Maglione M, Estournès C, Pate M, Ganne J P 2008 Appl. Phys. Lett. 92 042902
[26] Zhu X H, Zheng D N, Peng W, Li J, Chen Y F 2006 Mater. Lett. 60 1224
[27] Goux L, Gervais M, Gervais F, Catherinot A, Champeaux C, Sabary F 2002 Mater. Sci. Semicond. Process. 5 189
[28] Wang S X, Hao J H, Wu Z P, Wang D Y, Zhuo Y, Zhao X Z 2007 Appl. Phys. Lett. 91 252908
[29] Zhi Y, Liu D, Qu W, Luan Z, Liu L 2007 Appl. Phys. Lett. 90 042904
[30] Feng Z, Chen W, Tan O K 2009 Mater. Res. Bull. 44 1709
[31] Qin W F, Zhu J, Xiong J, Tang J L, Feng X 2007 J. Electron. Sci. Technol. 5 303
[32] Qin Y X, Li Z, Liang W X, Liu N, Zhao P 2018 Piezoelectr. Acoustoopt. 40 95 (in Chinese) [秦杨晓，李卓，梁文学，刘娜，赵鹏 2018 压电与声光 40 95]
[33] Xu Q, Zhang X F, Huang Y H, Chen W, Liu H X, Chen M, Kim B H 2009 J. Alloys Compd. 488 448
[34] Qi W H, Wang Z, Li X F, Yu R C, Wang H H 2022 Acta Phys. Sin. 71 178103 (in Chinese）[戚炜恒，王震，李翔飞，禹日成，王焕华 2022 物理学报 71 17 178103]
[35] Zhang Q W, Zhai J W, Yue Z X 2013 Acta Phys. Sin. 62 237702 (in Chinese）[张奇伟，翟继卫，岳振星 2013 物理学报 62 23 237702]
[36] Zhang Q W, Zhai J W, Kong L B, Yao X 2012 J. Appl. Phys. 112 124112
[37] Zhang J J, Zhai J W, Chou X J, Shao J, Lu X, Yao X 2009 Acta Mater. 57 4491
[38] Verma A, Raghavan S, Stemmer S, Jena D 2015 Appl. Phys. Lett. 107 192908
[39] Chen Y, Zhou H J, Xie S X, Xu Q, Zhu J G, Wang Q Y 2021 Adv. Mech. 51 755 [陈渝，周华将，谢少雄，徐倩，朱建国，王清远 2021 力学进展 51 755]
[40] Chen J H, Su X, Yuan T, Tang W B, Ding S C, Shi Y, Li F M, Chen K, Yu Y, Zhang H C, Zhu S Y, Yuan G L, Lu J 2025 Adv. Mater. Interfaces 12 2400949
[41] Tang Q W, Shen M R, Fang L 2006 Acta Phys. Sin. 55 1346 (in Chinese）[唐秋文，沈明荣，方亮 2006 物理学报 55 1346]
[42] Zhu X H, Chong N, Chan H L, Choy C, Wong K, Liu Z G, Ming N B 2002 Appl. Phys. Lett. 80 3376
[43] Lu X M, Huang F Z, Zhu J S 2020 Acta Phys. Sin. 69 127704 (in Chinese）[吕笑梅，黄凤珍，朱劲松 2020 物理学报 69 127704]
[44] Alema F, Pokhodnya K 2015 J. Adv. Dielectr. 5 1550030
[45] Sahoo S K, Misra D, Sahoo M, MacDonald C A, Bakhru H, Agrawal D C, Mohapatra Y N, Majumder S B, Katiyar R S 2011 J. Appl. Phys. 109 064108
[46] Zhang J R, Chen C, Xiang S Q, Zhang J C, Qi Q, Huang R, Yu Y, Chen K, Han Z D, Yuan G L, Liu J M, Zhu J S 2022 Mater. Res. Express 9 106303
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