ISO 22278:2020
(Main)Fine ceramics (advanced ceramics, advanced technical ceramics) — Test method for crystalline quality of single-crystal thin film (wafer) using XRD method with parallel X-ray beam
Fine ceramics (advanced ceramics, advanced technical ceramics) — Test method for crystalline quality of single-crystal thin film (wafer) using XRD method with parallel X-ray beam
This document specifies the test method for measuring the crystalline quality of single-crystal thin film (wafer) using the XRD method with parallel X-ray beam. This document is applicable to all of the single-crystal thin film (wafer) as bulk or epitaxial layer structure.
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General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 22278
First edition
2020-08
Fine ceramics (advanced ceramics,
advanced technical ceramics) — Test
method for crystalline quality of
single-crystal thin film (wafer) using
XRD method with parallel X-ray beam
Reference number
©
ISO 2020
© ISO 2020
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ii © ISO 2020 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Fundamentals . 3
5 Devices and instruments. 3
5.1 Schematic diagrams . 3
5.2 X-ray generator . 4
5.3 X-ray mirror . 5
5.4 Monochromator . 5
5.5 Sample attachment . 5
5.6 Goniometer. 5
5.7 Detector . 5
5.8 Instrument calibration . 5
6 Preparation of sample . 6
7 Test method and procedure . 6
7.1 Optics alignment . 6
7.2 Sample alignment . 6
7.3 Adjusting the initial position of goniometer . 7
7.3.1 Symmetric diffraction . 7
7.3.2 Asymmetric diffraction . 9
7.4 Microscopic position adjustment of goniometer (Φ and χ axes) and ω scan . 9
7.4.1 Symmetric diffraction . 9
7.4.2 Asymmetric diffraction .12
7.5 Crystalline quality measurement method of single-crystal wafer .16
7.5.1 General.16
7.5.2 Selecting the flat zone position of wafer .16
7.5.3 Arranging the fixed size of the square .17
7.5.4 Measuring the FWHM value of RC .17
7.5.5 Interference effect by the wafer's curvature .17
7.5.6 Doped epitaxy film on a single-crystal thin film substrate .17
8 Data analysis .18
9 Test report .18
Annex A (informative) Example of d-spacing, 2θ, χ value (tilt angle) and relative ideal
intensity of the symmetric and asymmetric diffraction on the SiC single-crystal thin
film (wafer) .20
Annex B (informative) Determination of d-spacing, 2θ, χ value (tilt angle) and relative ideal
intensity for the symmetric and asymmetric diffraction on the single-crystal thin
film (wafer) .22
Annex C (informative) Results of interlaboratory test .27
Bibliography .29
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
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This document was prepared by Technical Committee ISO/TC 206, Fine ceramics.
Any feedback or questions on this document should be directed to the user’s national standards body. A
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iv © ISO 2020 – All rights reserved
Introduction
Single crystals are important in many applications ranging from synthetic gemstones for jewellery to
hosts for solid-state lasers. For some applications, ceramic materials are prepared as single crystals.
When used as substrates for thin film growth (such as gallium-on-sapphire technology or the growth
of superconductor thin films) it is the crystalline perfection of a single crystal that is important. Wide
bandgap semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) have drawn a lot of
attention in power applications due to their superior material properties such as high critical electric
field resulting in a minimum of 10 times higher breakdown voltage or a 100 times smaller on-resistance
than Si. These unique properties of SiC and GaN materials have made them promising candidates for
future high-power, high-frequency semiconductor devices. In optical applications, such as the use
of ruby and yttrium–aluminium–garnet (YAG) for laser hosts and quartz and sapphire for optical
windows, single crystals are used to minimize scattering or absorption of energy. In piezoelectric
materials, such as quartz, the optimum properties are obtained in single-domain single crystals. In
addition, there are many other applications that require the optical, electrical, magnetic or mechanical
properties of ceramic single crystals.
Substrate diameters for the single crystal have been steadily increasing since the commercial
introduction of substrates in 1990 and crystal defects have been greatly reduced in the past 15 years.
Commercial devices are available, but their widespread use will depend on the ability of growers to
make large, inexpensive, defect-free materials available.
While various methods for measuring the defect of single-crystal thin films have been presented until
now, the most typical method for measuring the crystalline quality (degree of average defect) of single-
crystal thin films that have a wide area (e.g. 2 inches, 4 inches, 6 inches) is the X-ray diffraction (XRD)
method with parallel X-ray beam. However, this method can easily create a great error margin as the
result value is analysed to be very different depending on the measuring process and conditions of the
user or the pre-treatment of samples, for example. A standard on universal measurement methods and
conditions, therefore, is absolutely necessary.
INTERNATIONAL STANDARD ISO 22278:2020(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Test method for crystalline quality of single-
crystal thin film (wafer) using XRD method with parallel
X-ray beam
1 Scope
This document specifies the test method for measuring the crystalline quality of single-crystal thin
film (wafer) using the XRD method with parallel X-ray beam. This document is applicable to all of the
single-crystal thin film (wafer) as bulk or epitaxial layer structure.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
single crystal
crystalline material having identical atomic arrangement on all areas of the material
3.2
off-cut angle
angle that a specific crystallographic orientation forms with surface in a single-crystal thin film (wafer)
Note 1 to entry: Off-cut angle is a key condition determining the growth behaviour of thin film during epitaxial
growth on a single-crystal thin film (
...
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