Growth of Piezoelectric <Li_2> <B_4> <O_7> Single Crystal and its Applications to Ultra High Frequency Surface Acoustic Wave Devices

压电<Li_2><B_4><O_7>单晶的生长及其在超高频声表面波器件中的应用

• 批准号: 60460122
• 负责人: SHIOSAKI Tadashi
• 金额: $ 4.48万
• 依托单位: Kyoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1985
• 资助国家: 日本
• 起止时间: 1985 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-60460122/
• 关键词: Lithium Tetraborate; Surface Acoustic Wave; Bulk Acoustic Wave; Temperature Coefficient of Delay; Coupling; 表面波共振子; 機械的品質係数; 結合係数

Lithium tetraborate ( <Li_2> <B_4> <O_7> ) has attracted much attention as a promising candidate for the new surface acoustic wave (SAW) and also as bulk acoustic wave (BAW) materials because of its very low temperature coefficient of frequency (TCF) and high coupling. The object of this project is growth of good quality <Li_2> <B_4> <O_7> (LBO) crystal and its applications. The abstract is as follows:1. Transparent, core-free and good quality single crystals of <Li_2> <B_4> <O_7> , up to 23mm in diameter and 80mm in length, have been successfully grown from a congruent melt at rotation rates around 40rpm and growth rate of 1.7mm/h by an automatic diameter control (ADC) of the Czochralski method. It has been pointed out that the growth rate will become higher by making the rotation rate higher and the temperature profile steeper at the solid-melt boundary.2. All the dielectric, elastic and piezoelectric constants and their first- and second-order temperature coefficients have been determined in detail by measuring resonant and antiresonant frequencies.3. The existance of orientations of lithium tetraborate with zero temperature coefficient of delay or frequency have been predicted on the basis of the material constants determined by the present authors, and confirmed experimentally for the Rayleigh and leaky SAW and BAW. There are useful substrate orientations for SAW devices with zero TCD around (0゜,78゜,90゜), (0゜,90゜,78゜) and (45゜,90゜,90゜), where <k_s^2> is approximately 0.8-1%. However, among these substrates, the (45゜,90゜,90゜) is the most suitable substrate, Further, it has been confirmed that the temperature compensated cuts for rotated Y-cut bulk wave devices exist at <theta> of 32゜ for the quasi-longitudinal mode and <theta> of 53゜ for the quasi-shear mode.4. The resonater with Q of 3400 have been successfully fabricated.

四硼酸锂 ( <Li_2> <B_4> <O_7> ) 作为新型表面声波 (SAW) 和体声波 (BAW) 材料的有希望的候选者而备受关注，因为它具有非常低的频率温度系数 (本项目的目标是生长优质<Li_2><B_4><O_7>（LBO）晶体及其应用。摘要如下： 1．高质量的<Li_2> <B_4> <O_7>单晶，直径可达23mm，长度为80mm，已通过自动熔体以约40rpm的转速和1.7mm/h的生长速率成功地从同质熔体中生长出来。直拉法的直径控制(ADC) 已经指出，通过提高旋转速率和使固熔体的温度分布更陡，生长速率将会变得更高。 2. 通过测量谐振和反谐振频率详细确定了所有介电常数、弹性常数和压电常数及其一阶和二阶温度系数。3. 零延迟温度系数的四硼酸锂的取向的存在。频率已根据本作者确定的材料常数进行了预测，并通过瑞利和泄漏 SAW 和 BAW 的实验得到了证实。 对于 TCD 为零的 SAW 器件，存在有用的基板方向。 (0゜,78゜,90゜)、(0゜,90゜,78゜)和(45゜,90゜,90゜)，其中<k_s^2>约为0.8-1%。基材中，(45゜,90゜,90゜)是最合适的基材，此外，已证实温度旋转Y切割体波器件的准纵模<theta>为32°，准剪切模<theta>为53°存在补偿切口。4．成功制作了Q值为3400的谐振器。 。

项目成果

塩崎忠: to be published in Proceedings of IEEE 1986 International Symposium on the Applications of Ferroelectrics,IEEE New York,(June,9-11,1986;Bethlehem,Pennsylvania). (1987)

Tadashi Shiozaki：发表于 IEEE 1986 国际铁电体应用研讨会论文集，IEEE 纽约，（1986 年 6 月 9 日至 11 日；宾夕法尼亚州伯利恒）（1987 年）。

Masatoshi Adachi: "Temperature Compensated Piezoelectric Lithium Tetraborate Crystal for High Frequency Surface Acoustic Wave and Bulk Wave Device Applications" 1985 IEEE Ultrasonic Symposium Proceedings (Oct. 16-18, 1985, San Francisco, California). 85CH

Masatoshi Adachi：“用于高频表面声波和体波器件应用的温度补偿压电四硼酸锂晶体”1985 IEEE 超声波研讨会论文集（1985 年 10 月 16-18 日，加利福尼亚州旧金山）。

安達正利: 1985 IEEE Ultrasonics Symposium Proceedings,85CH2209-5(Oct.16-18,1985,San Francisco,California). 1. 228-232 (1986)

Masatoshi Adachi：1985 年 IEEE 超声波研讨会论文集，85CH2209-5（1985 年 10 月 16-18 日，加利福尼亚州旧金山）1. 228-232 (1986)。

Tadashi Shiosaki: "Elastic, Piezoelectric, Acousto-Optic and Electro-Optic Properties of <Li_2> <B_4> <O_7> " Proceedings of the 5th Symposium on Ultrasonic Electronics, Tokyo 1984 Japanese Journal of Applied Physics, Suppl. 24-1. 24. 25-27 (1985)

Tadashi Shiosaki：“<Li_2> <B_4> <O_7> 的弹性、压电、声光和电光特性”，第五届超声波电子学研讨会论文集，东京 1984 年 日本应用物理学杂志，增刊。

Tadashi Shiosaki: "Growth and Properties of Piezoelectric Lithium Tetraborate Crystal for BAW and SAW Devices" to be published in Proceedings of IEEE 1986 International Symposium on the Applications of Ferroelectrics, IEEE New York (June 9-11, 1986, Bethl

Tadashi Shiosaki：“BAW 和 SAW 器件的压电四硼酸锂晶体的生长和特性”将发表在 IEEE 1986 国际铁电应用研讨会论文集，IEEE 纽约（1986 年 6 月 9 日至 11 日，Bethl）