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Single Crystalline Substrates MgO, ZnO, GGG, GSGG ...
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InP
GGG
Film technologies are becoming more and more important for the development of modern sciences and technologies. The development of film technology needs various and high quality single crystalline substrates. Firstly, the cell parameter of the substrate must match with the film to be grown on the substrate and it varies well, so that only special single crystal which has certain lattice constant, correct orientation and high fabrication accuracy can be used for the film. Secondly, the substrate crystal must be structure perfectly, and the crystal structure defect such as twin and inclusion must be as few as possible. The surface of the substrate must be polished to very high flatness and micro roughness (the test result of AFM should be better than a few angstrom in an 5x5um area, for example). The substrate must be able to stand to high, low temperatures and chemical environment during the film growth and use process. Also some physical, mechanical properties are necessary for the substrate. For example, the microwave dielectric loss must be very low for the substrates used in microwave communication.
   Gadolinium Gallium Garnet (GGG, Gd3Ga5O12) is a magneto-optical and microwave substrate. It is the best substrate material for infrared optical isolator (1.3 and 1.5um), which is a very important device in optical communication. It is made of YIG or BIG film on the GGG substrate plus birefringence parts. Also GGG is an important substrate for microwave isolator and other devices. Its physical, mechanical and chemical properties are all good for the above applications.
   Zinc Oxide (ZnO) can be grown as a single crystal semiconductor with very interesting properties. The bandgap is in the 3.4 eV range which makes it attractive for many of the blue and violet applications in opto-electronics as well as UV devices. It is available in bulks, in wafers of up to 2 inches, which gives it a major advantage over Gallium Nitride and other group III Nitrides.
   ZnO also has the potential to become the substrate material of choice for GaN. Like GaN it has a wurtzite structure, with lattice constants closely matched to GaN (a=3.249, c=5.205). ZnO is exactly lattice matched to InGaN with a 22% In content. Perhaps most importantly it is a soft compliant material that is believed to probably and may take up the lattice stress in preference to the growing GaN layer. It suffers from the drawback that it dissociates in ammonia at temperatures above 600°C. With its wide bandgap, Zinc Oxide could prove very useful in optical applications as well as many high speed electronics. ZnO may also be used as a substrate for epitaxial growth.
   MolTech has been supplying high quality wafers for semiconductor industries since 1995. If you need any of these crystal substrate, what ever small or larger quantity, please feel free to contact us.

Typical Properties:

Substrates
MgO
ZnO
ZrO2
Al2O3 (Sapphire)
Gd3Ga5O12 (GGG)
(Gd3-x Cax Ga5-x-2y Mgy Zrx-y O12) GGG:Ca,Mg,Zr
(Gd3Sc2Ga3012) GSGG
Crystalline
Cubic Fm3m
Hexagonal
 Cubic
 Hexagonal

cubic  m3m  Garnet

cubic  m3m  Garnet

-

Lattice Constant
a=4.13A
a= 3.252, c = 5.313
 a = 5.147

 a = 4.748,  c =12.97

a=12.383 Å
a=12,496 Å
a=12,560 Å
Melting Point
2800°C
1975°C
 2700°C
 2040°C
2098°C
2098°C
2098°C
Density
3.58
5.7 g/cm3
 6.0g/cm3
 3.98g/cm3
7.08 g/cm3
7.08 g/cm3
7.08 g/cm3
Specific Heat
0.21cal/gC (RT)
0.125 cal/g℃
 
 0.181cal/g℃
0.3812J/g°K
-
-
Mohs Hardness
5.5
4
 8-8.5
 9
6
6
6

Thermal Expansion Coefficient

11.2 x 10-6/C
2.90 x 10-6/°K
 -
 5.810-6/℃
9.18x10-6k-1
-
-
Dielectric Constant
9.65 (1x102 - 1x108 Hz)
-
-
-
12.11
-
-
Thermal conductivity
-
0.006 cal/cm/°K
-
-
7.05W/m°K
-
-
Refractive index at 26.0°±0.4
-
-
-
-
1.945
-
-
Dislocations density, cm-2
-
< 100
-
-
7
-
-
Surfaces defect density, cm-2
-
-
-
-
0.5
-
-
Flat orientation
-
<0001>
-
-
primary - (II0)±2.0°
secondary - (II2) 90±5°
from the primary flat
-
-
Max. Dimensions
-
Ø76 mm (3")
-
Ø105 ± 5 x 130 mm
Ø76 mm
Ø76 mm

We also supply elements made from mentonied crystals with different cross-sections and dimensions according to customer specifications.

I N Q U I R Y    F O R M :

Material:
Quantity of elements:
Application:

polished sites:

BLOCK    or  BLOCK
 a-b b-c a-c
or d  
Orientation:
(if applicated)
Dimensions/Tolerances:
For example:
10.0 +/- 0.1
AR-coating or electrodes:
a = mm;
c = mm
b = mm or
dia. = mm;
This field is for additional information such as application,
comments, add. requirements etc.

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