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.
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.