Ultrasonic Microspectroscopy of Ultra-High-Quality Synthetic a-Quartz

利用线聚焦光束（LFB）和平面波（PW）超声材料表征（UMC）系统，应用超声微光谱技术建立了体声波（BAW）和表面声波（SAW）器件合成α-石英晶体的评价技术，并精确测量了声学物理常数。本研究的目的是为工业和科学领域合成α-石英提供一个新的、世界性的指导方针和标准。提高了LFB超声材料表征系统和本体超声光谱系统的测量精度。建立了测定32类晶体声学物理常数的新方法，以及测定合成α-石英和天然α-石英的声学物理常数的新方法：(1)建立了一种新的BAW方法，可以准确测定32类晶体声学物理常数的所有独立分量。这种方法需要使用X、Y、z切割试样和几个旋转Y切割试样测量更长的纵向和剪切速度、介电常数和密度。对saw级合成α-石英进行了验证。结果提供了BAW速度在±0.2 m/s（±0.004%）精度范围内的常数。(2)为了比较天然α-石英和人工α-石英的声学特性，采用X、Y、z切割试样测量了α-石英的纵向、剪切速度和LSAW速度。速度差均在1.00 m/s以内，表明天然石英的声物理常数与合成石英的声物理常数非常接近。(3)利用LFB/PW UMC系统，通过测量LSAW速度和BAW速度来确定32类晶体的所有常数。该方法适用于天然α-石英。(4)采用本文开发的BAW方法，确定了天然石英的精确常数值。弯曲速度。对几种不同生长条件下合成α-石英晶锭制备的试样进行了LSAW速度、密度和晶格参数的测量。检测到轻微的速度差异。在不同的传播方向和传播模式下，速度随杂质浓度，尤其是OH含量的变化有所不同。晶格常数a不变，但c随着OH含量的增加而增大。少

Ultrasonic microspectroscopy technology, using the line-focus-beam (LFB) and plane-wave (PW) ultrasonic material characterization (UMC) system, has been applied to establish evaluation techniques for synthetic α-quartz crystals for bulk acoustic wave (BAW) and surface acoustic wave (SAW) devices and to accurately measure the acoustical physical constants. The purpose of this study was to provide a new, worldwide guideline and standard for synthetic α-quartz in the industrial and scientific fields.1. Measurement accuracies of the LFB ultrasonic material characterization system and bulk ultrasonic spectroscopy system have been improved.2. Development of new methods for determining the acoustical physical constants of class-32 crystals and determination of the constants of synthetic and natural α-quartz:(1) A new BAW method to accurately determine all of the independent components of the acoustical physical constants for class-32 crystals was developed. This method requires to measure lon … More gitudinal and shear velocities, dielectric constants, and density, using X-, Y-, and Z-cut specimens and several rotated Y-cut specimens. The demonstration was conducted for SAW-grade synthetic α-quartz. The results provided the constants that give BAW velocities within an accuracy of ±0.2 m/s (±0.004%).(2) To compare the acoustic properties between natural and synthetic α-quartz, longitudinal and shear velocities, and LSAW velocities were measured using X-, Y-, and Z-cut specimens. All the velocity differences were within 1.00 m/s, and it was clarified that the acoustical physical constants of the natural quartz, were, very similar to those of synthetic quartz.(3) Another new method for determining all the constants for class-32 crystals by measuring LSAW velocities in addition to BAW velocities for there principal X-, K and Z-cut specimens using the LFB/PW UMC system was developed. This method was applied for natural α-quartz.(4) Precise values of the constants for natural quartz were also determined using the BAW method developed here.3. BAW velocities. LSAW velocities, density and lattice parameters were measured for the specimens prepared from several synthetic α-quartz crystal ingots with different growth conditions. Slight velocity differences were detected. The velocity changes related to the impurity concentration, especially OH content, were different for the propagation directions and propagation modes. Lattice constant a was constant, but c became larger as the OH content became higher. Less