Some standard content:
GB/T3353—1995
This standard is equivalent to IEC758:1993 Specifications and Guidelines for the Use of Artificial Quartz Crystals Part 2: Guidelines for the Use of Artificial Quartz Crystals. Artificial quartz crystals are extremely important functional materials in the market. They have excellent piezoelectric and optical properties and are widely used in electronic components and optical equipment. In April 1993, IEC/TC49 issued the revised 1EC758 "Specifications and Guidelines for the Use of Artificial Quartz Crystals". The content of the second edition has been greatly revised, mainly in terms of the method for evaluating the quality of artificial quartz crystals, which has been changed from the original good value to direct measurement using infrared quality index values, the level of inclusion penetration has been reclassified, and the requirements for corrosion tunneling have been added. The measurement methods for these three important technical parameters have been specified. In view of the above major revisions, the national standard GB33522 for artificial quartz crystals was revised in 1994 according to the new IEC 758 version, so this guideline has also been revised accordingly. This standard will replace GB3353—82 from the date of entry into force. This standard was proposed by the Ministry of Electronics Industry of the People's Republic of China. This standard is under the jurisdiction of the Standardization Institute of the Ministry of Electronics Industry. The drafting units of this standard are: State-owned Morning Star Radio Equipment Factory and the Standardization Institute of the Ministry of Electronics Industry. The main drafters of this standard are: Zhang Yi, Jing Hezhen, Xie Xianzhen, and Liu Chenggou. CB/T 3353—1995
IEC Foreword
1) IEC (International Electrotechnical Commission) is a worldwide standardization organization composed of national electrotechnical committees (IEC National Committees). The purpose of IEC is to promote international cooperation on standardization issues in the field of electrical and electronic engineering. To this end, among other activities, IEC publishes international standards. The formulation of international standards is undertaken by technical committees. Any IEC National Committee concerned with the content involved may participate in the formulation of international standards, and any international, governmental and non-governmental organization associated with IEC may also participate in the formulation of international standards. IEC and the International Organization for Standardization (ISO) maintain close cooperation based on conditions agreed upon between the two organizations. 2) IEC formal resolutions or agreements on technical issues are made by technical committees to which national committees with special interest in these issues are added, and represent as far as possible the broad international consensus on the issues involved. 3) These resolutions or agreements are published in the form of standards, technical reports or guidelines, which are recommended for international use and, in this sense, are recognized by the national committees.
4) In order to promote international unity, each IEC national committee has the responsibility to make its national and regional standards use IEC standards as much as possible. Any differences between IEC standards and corresponding national or regional standards should be indicated in the national or regional standards. 5) IEC has not established any procedures for the use of the approval mark. IEC is not responsible for claiming that a product complies with the corresponding IFC standard. International Standard IEC758 was prepared by IEC Technical Committee 49 - Piezoelectric and Dielectric Devices for Frequency Control and Selection. This second edition of the standard replaces the first edition published in 1983 and Supplement No. 1 published in 1984. The text of this standard is based on the following documents: otss
49(CO)218
Voting report
49(CO)252
Voting approval Details of this standard can be found in the voting report listed in the table. Appendix A, Appendix B and Appendix C are for reference only. 1 Scope
National Standard of the People's Republic of China
Guide to the use of synthetic quartz crystal
Guide to the use of synthetic quartz crystal This standard gives the guide to the use of synthetic quartz crystal. GB/T.3353—1995
eq IEC 758.1993
Replaces GB3353-82
This standard is applicable to guide the most effective use of artificial quartz crystals. This standard does not involve all the characteristics of artificial quartz bodies. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T 3352—94 Artificial quartz crystal
3 Overview
3.1 Artificial quartz crystal
Artificial quartz crystal is grown by hydrothermal temperature difference method. At low temperature, the high pressure container (autoclave) is partially filled with alkaline growth solvent (such as sodium carbonate or sodium hydroxide). The seed crystal is placed in the upper space of the autoclave, and the broken quartz culture body is placed at the bottom of the autoclave, which is then sealed and heated. Keep the temperature of the autoclave lower than the temperature at the bottom. Therefore, the culture body solute is transferred to the seed crystal by convection and deposited. The shape, size and physical properties of the growing body are related to the seed orientation, seed size and growth conditions. A well-controlled growth process can ensure the consistency of the shape and size of the quartz body and the uniformity of quality. 3.2 Names of crystal axes and crystal planes
Figure 1a shows a quartz crystal with all natural crystal planes. These crystal planes do not often appear in artificial quartz. Figure The artificial quartz crystal shown in Figure 1h is grown on a seed crystal with a specific orientation. Therefore, the crystal shapes shown in Figure 1a and Figure 1h are different.
3-3 Seed Crystal
Choosing some seed crystals with standard orientations, it is possible to economically grow artificial quartz crystals for making quartz crystal components. Artificial quartz crystals grown on seeds with small rhombus cuts are mainly used to process high-frequency crystals of thickness shear vibration mode and medium-frequency crystals of face shear vibration mode. Artificial quartz crystals grown on seeds with Z' cuts are mainly used to process low-frequency crystals of expansion and bending vibration modes.
On the surface of the seed crystal in the artificial quartz crystal grown by !, there is often a thin layer of bubbles and inclusions. 3.4 Crystal shape and size
The original artificial quartz crystal has only specific growth faces. Figure 2 shows the typical shape of a crystal grown on a seed crystal with a small X-axis dimension? If you use other proportions of cut seed crystals or other cut seed products, you will grow quartz products of other shapes. The size of the artificial quartz crystal is determined by three mutually perpendicular X, Y, and Z (or Z') dimensions, which are the dimensions along the X axis, Y' axis, and Z (or Z') axis.As shown in Figure 3. The selection of the scale should take into account: on the one hand, making the growth process economical; on the other hand, making the crystal piece have a high utilization rate. At the same time, it should be noted that the product size is determined by negotiation between the manufacturer and the user. The State Bureau of Technical Supervision approved on December 22, 1995 and implemented on August 1, 1996
GB/T3353-1995
Quartz crystals grown by quartz have specific growth planes, such as the m or z plane at both ends of the Y axis or Y axis, so the effective size used to cut the crystal piece is smaller than the nominal scale. Due to the uneven surface of the male surface and the possibility of non-parallelism, it is actually very difficult to accurately measure the smallest 7 dimensions, and it is also very difficult to achieve precise scale tolerances. For these reasons, when the user has a higher dimensional tolerance requirement than the manufacturer, the use of partially processed quartz raw material (sometimes called pre-sized quartz or quartz rod) should be considered.3-5 Growth Zones
The deposition of solute on each growth surface is continuous, so the crystal quality is basically uniform. However, the deposition method is different in different zones, so there are different zones along different directions of growth, and these zones have different properties. Among the most common growth zones mentioned in this standard, the 7 zone has the best crystal quality, followed by the large X zone, and then the small S zone. Therefore, it is recommended that the crystals of thickness shear and face shear vibration modes should be cut completely or mostly from the 7 zone, and it is recommended that the electrode zone of the best quality crystals only contain crystal material from the Z zone. The small X zone has the worst quality and is generally not used to process high-frequency crystals. Figures 3a and 3b are typical examples of AT-cut and X-cut crystals cut from appropriate long zones. 4 Methods for characterizing the quality of synthetic quartz crystals
The extent of structural and chemical defects in synthetic quartz crystals depends on the growth conditions and the dopants used, which are related to the growth rate with two important practical consequences. The first consequence is a decrease in the α level of the crystal (i.e. an increase in the α value), and secondly, an inconsistency in the cut angles required to obtain a particular frequency stability.
Originally, the Q value of quartz crystal components was used to indicate the quality of the crystal material. Making a 5MHz 5th overtone standard crystal component will ensure that the Q value reflects internal losses but not assembly losses and slight differences in processing technology between manufacturers. Such components are large and sometimes cannot be cut from the z region.
When the extinction coefficient α was used to indicate the Q value of the crystal, it soon almost completely replaced the direct Q value measurement. As a means of indicating the characteristics of the crystal, the internal Q value method has its own capabilities and advantages. It can measure small growth zones and can also resolve details of the growth zone structure. These tests are non-destructive, inexpensive, and fast. When αs51o is less than 0.06cm-1 (C grade>), the dispersion of the most focal cutting angle is very small and can be compared with the dispersion of natural quartz crystal. Therefore, it is recommended to use this product to manufacture high-frequency temperature characteristics. Good control of the growth process can ensure the consistency of the α value of a batch of products. The samples in the batch should include an artificial quartz crystal with the maximum thickness along the Z or Z' axis. Since the a value is proportional to the growth rate, the sample with the largest thickness in the batch has the largest value. Therefore, the test using this sampling method can meet most applications. Another measurement specified in GB/T3352 for evaluating artificial quartz is to test the frequency-temperature characteristics of crystal components. The provision for the cutting angle is to select a crystal with a linear slope of the frequency-temperature characteristic and sensitive The angle that changes with the cutting angle. The regulations on the shape and size of the measured component should be suitable for determining the accurate cutting angle, but the Q value of this crystal component is affected by processing and assembly, so it cannot be used to evaluate the value of the quartz crystal.
4.1 Infrared radiation absorption method
The crystal body contains certain groups that can absorb infrared radiation at a specific wave number. The most common impurity group in artificial quartz crystal is 0H with hydrogen bonds. Its quantity can be determined by the infrared extinction coefficient at a certain wave number between 34100 and 3600cm1. The concentration of OII is related to the loss of mechanical energy in the quartz crystal, so there is a certain relationship between infrared absorption and Q value. Figure 4 is a typical positive curve obtained from each measurement point.
The test method is according to GH/T3 352-94, 5.5. The infrared absorption passband is used to determine the Z zone of the body structure. The absorption in the small X zone is different from the absorption in the Z zone. It should also be noted that due to the different selected conditions, the infrared extinction coefficient obtained is also different. These conditions are: the size of the window into the infrared beam; the relative position of the test point and the seed crystal; the polarization plane; the humidity and temperature of the measurement environment; the different bias voltages of the infrared spectrophotometer. The international cycle test of "GB/T3353-1995
Infrared extinction coefficient of artificial quartz" clearly shows that the bias voltage of each infrared photometer is different, and it can be calibrated using a standard quartz plate.
4.2 Inspection of the quality of artificial quartz crystals Other methods There are many methods for testing the structural integrity of artificial quartz crystals, but the quantitative relationship between it and the electrical properties of crystal components has not yet been fully established. The infrared absorption method described above is an exception, which can be used to evaluate the Q value of the crystal. 4.2.1 Visual inspection
Quartz crystal components should avoid too many inclusions as much as possible. 4.2.2 Chemical etching method
Chemical etching is widely used to test twins of natural quartz, but this method is not necessary for artificial quartz because twins of artificial quartz are extremely rare. This method can be used to reveal corrosion pits and corrosion tunnels as a measure of the number of dislocations. 4-2.3 X-ray morphology method
Y-ray or X-ray radiation can be used to observe the overall distribution of impurities in the crystal. Because the degree of radiation blackening is related to the impurity concentration and the growth zone.
X-ray diffraction patterns can provide useful data on the integrity of the crystal, using a divergent X-ray beam to produce clear Laue patterns on low α crystals. Lang's X-ray topography is useful for identifying the distribution of crystal structure defects. However, it should be noted that there is still a lack of quantitative relationship between all these methods and the overall electrical properties of quartz crystal components. 5 Grades of artificial quartz crystals
5.1 Grades
The values of crystals are divided into six grades. Grades Aa, A and B can be used for the highest quality crystal components. Grade C is mainly suitable for high-frequency quartz crystal components that have not only good temperature characteristics but also low α values (high Q values). Grades D and F are mainly for low-frequency quartz crystal components. For low-frequency components, the first consideration is to use cheap large crystals. 5.2 Optional grades when orderingwww.bzxz.net
5-2.1 Etching tunnel
Five grades are specified. Grades 1 and 2 are used for special commercial quality crystal components, such as high fundamental frequency or commercial frequency SAW devices, or for special processes such as chemical etching. Grades 3 and 4 are suitable for manufacturing bulk components for most technologies, and grade 5 is suitable for most general-purpose bulk components. 5.2.2 Inclusions
Four grades are specified. Ia and 1 are used for special high-quality optical applications, such as VCRs, or for photolithography, 2 are generally used for high-frequency/high-quality bulk wave or SAW resonators, and 3 are used for most professional and industrial crystal components. 5.2.3 Aluminum content
Low aluminum content also reduces the monovalent ions associated with aluminum (mainly sodium and). Therefore, when radiation resistance and frequency change prevention are required, the aluminum content must be controlled.
6 Ordering items
The following items should be specified when ordering, and standard grades and standard values should be used as much as possible; a) Type of deuterated aluminum (right-handed or left-handed);
b) Orientation of the seed;
c) Size;
d) α level:
e) Additional technical requirements level only when required. Left-handed quartz
Left-handed quartz
GB/T3353—1995
Stone spiral stone
Several natural quartz crystals
b artificial quartz crystals
Angstrom quartz
Figure 1 Names of quartz crystal axes and faces
GB/T3353—1995
Large x area
Figure 2 Artificial quartz crystals grown with small x-size Z-cut seed crystals, when using other When cutting seed crystals or other types of seed products of other proportions, that is, growing crystals of other shapes, Z zone
35°16
Location of 0° oriented AI slices in right-handed artificial quartz Z zone
Small X zone
Location of hx slices
Large x zone
Too x zone
Figure 3 Typical examples of AT slices and X slices cut from 7. zone of artificial quartz crystal growth Q×10
GB/T 3353—1995
? In the early 1900s, there was a relationship curve between the infrared absorption coefficient of artificial quartz and the Q value. The recently recalibrated /as relationship includes measurements using modern spectrophotometers without case light, and c can be very close to the Q value on the old curve,As shown in the figure, it adds 0.0lam unit adjustment to the measured value and corrects it to the corresponding Q value. Although the amount of normalization in α is small, its impact on Q is obvious at high and low values.
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.