SPI Supplies Brand^® MgO Magnesium Oxide Single Crystal Substrates, Blocks, and Optical Components

Used by high temperature thin film superconductor researchers worldwide!
Purity better than 99.9%! Choose from cubic blocks or polished wafers.

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Molecular formula: MgO
Appearance: Optically clear crystalline solid
CAS#: 1309-48-4
EC #: 2151719
Molecular Weight: 40.30

The SPI Supplies MgO Single Crystal Substrate products are used widely for HTSC (high temperature superconductor) thin film coatings applications worldwide. There is also a growing amount of interest in using these substrates, because of their economical cost, for other applications that previously would not have justified the higher cost of MgO, such as for use as substrates for the III to V elements.

The standard orientation is along the (100) planes. Other orientations at the present time are not available.

The crystals are highly transparent, permitting good transmission down to the UV and IR ranges of the spectrum. No more does the analytical chemist have to use one substrate slide for UV (such as quartz) and another one for IR, with MgO, the same slide can be used for both types of analysis.

New applications are being found outside of the HTSC applications area, for example, in research studying the epitaxial effects of substrates on the crystallization of polymers. Other applications include the deposition of ferro electric thin film coatings on magnesium oxide substrates. And there are also growing applications for MgO in the field of plasma display panel (PDP) technology.

The products are available "epi-polished" on either one side or two sides and are available as standard products in the form of 0.5 mm thick "plates" or wafers (round discs). The most commonly asked for sizes are listed below as "standard" items, however we can produce our high quality MgO single crystal substrate materials in just about any size or shape needed, up to 3" (75 mm) diameter or square. They are also available as a standard product in 10 mm cubes. Just let us know your requirements and if in wafer form, whether polished two sides or just one side.

Because MgO tends to be hygroscopic, the crystals are specially cleaned and packaged in order to result in a very long shelf life.

Other information about the SPI MgO Single Crystal products:

Physical Analysis:

Crystal Type:	Cubic
Lattice Constant:	4.212 Å
Density	3.585 g/cm³
Melting Point:	2800° C/5072° F
Dielectric Constant:	9.8
Loss Tangent:	9x10^-3 @ 10 GHz
Coefficient of Thermal Expansion:	8.0 x 10^-6/° C (at 100° C)
Hardness (Mohs scale):	5.8
Thermal conductivity (C.G.S.):	0.09RT
Specific heat constant:	0.24
Vicker Hardness (100):	910
Refractive Index (60 nm):	1.74

Wafer Specifications:
Dimensions:	2" x 0.5 mm thick
Orientation:	(100) ± 1° C
Diameter:	50.8 +0/-0.05mm
Thickness:	0.5 +0/0.02mm
Flatness:	Radial flatness is better than 0.0025mm
Surface Roughness:	R_a < 0.5nm (typical 0.2 nm)
	R_max < 3.5 nm (typical 2.0 nm)
Polished Side:	Double sides epi-ready quality
Package:	Paper bag with vacuum

What constitutes quality in an MgO single crystal?
Because the main application of MgO single crystal substrates is for thin film deposition, not only must the purity be better than 99.9%, the solid matrix must be free of all inclusions. So this means that the starting boule of MgO, itself, must be strain free, but it must also be free of any and all bubbles. The presence of any bubbles in the boule would be a real problem when doing the slicing into wafers. If you are comparing prices, make sure you obtain credible information about the purity. Material described as being "better than 98% pure" is a far inferior product but is a lower price. But for quality work in thin film coatings research, the highest possible purity is needed. And that is why only the highest quality available is offered by SPI Supplies.

Impurity elements: The elemental composition of the 0.1%. This, not MgO (in other words, the impurities) is the following (in maximum ppm): Ca: 40, Al: 15, Si: 10, Fe: 50, Cr: 10, B: 5, C: 10

The SPI Supplies Brand of MgO Substrates, then are essentially free of twinning, strain defects and air bubbles.

The next most important consideration is the price. Many MgO substrate materials sold today do not have this level of purity. Yet the SPI MgO substrates are priced approximately at the same level as the materials with lower purities and materials exhibiting the defects of twinning, strain, and air bubbles.

If you do not see the size or shape you require, let us know. Although it would be a special order and set up costs are something to be considered, we are able to process special requests on an extremely favorable basis. As with any special order products, payment in advance is always required, and the order once accepted would be non-cancelable. Also, should one wish to do their own cleaving and polishing, with a little practice, you too could become an expert! Keep in mind that only a very few organizations have the ability to make this kind of material and because of the complexity of the process, there are size limitations on the largest size wafer or cube that can be made. For the present time, we are limited to wafers that are 2" (51 mm) in diameter.

Moisture sensitivity:
MgO is almost insoluble in water, however it should not be kept in a moist, high humidity environment for prolonged periods of time. For storage, it should always be kept in a desiccator cabinet. For polishing or repolishing MgO, non-aqueous media should be used at all times.

Tolerances in the dimensions of the blocks:
Unless otherwise stated, the crystals are cleaved to size, which leaves completely transparent crystals. However, the variation in the thickness can be as much as ± 2 mm for any given sample of the product. We can produce the MgO blocks to much tighter tolerances, however, to do that, we must use a diamond wire saw, but in addition to being very costly, it leaves the cut face milky white and opaque.

SPI MgO Single Crystal Wafers

Square wafers 10 mm x 10 mm (0.5 mm thick)	SPI #	Each	10+, Each	In Stock
1 side epi-polished	01841-AB	58.24	52.42	Yes
2 sides epi-polished	01842-AB	89.61	80.65	Yes
Round wafers 2" diameter (0.5 mm thick)
1 side epi-polished, each	01843-AB	576.15	518.54	Yes
2 sides epi-polished, each	01844-AB	657.45	591.71	Yes
SPI MgO Single Crystal Blocks
Cubes, Cleaved (100)
3-6 mm (for PDP applications) per 100g pack (size will vary from 3-6 mm)	01890-AB	426.64	383.98	No
10x10x10 mm, each	01845-AB	105.00	94.50	Yes
20x20x20 mm, each	01885-AB	450.00	405.00	No
25x25x25 mm, each	01886-AB	625.00	562.50	No
50x50x20 mm, each	01891-AB	2400.00	2160.00	No
SPI Single Crystal Optical Components Polished all parallel flat surfaces
Discs
25 mm Dia x 10 mm thick, each	01892-AB	1350.00	1215.00	No
50 mm Dia x 10 mm thick, each	01893-AB	2700.00	2430.00	No
Square Wafers 10mm x 10mm(0.7mm thick)
Unpolished	01888-AB	34.50	31.05	Yes
Bulk pack 100	01888-MB	2300.00	2070.00	No
Round Wafers 2" Diameter (0.7mm thick)
Unpolished	01889-AB	405.32	364.79	No

Storage conditions: Room temperature
Keep away from moisture by storing in a desiccator.
Non-hazardous from stand point of shipping

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SPI Supplies Brand® MgO Magnesium Oxide Single Crystal Substrates, Blocks, and Optical Components

SPI Supplies Brand^® MgO Magnesium Oxide Single Crystal Substrates, Blocks, and Optical Components