Sapphire
Optical
Material >>>
Sapphire
Single crystal Sapphire possesses a unique combination of excellent optical, physical and chemical properties, the most useful is that it is the hardest of the oxide crystals. Sapphire maintains its strength even at high temperatures. It has good thermal properties, excellent electrical and dielectric properties, and is chemically resistant to common acids and alkali at temperatures up to
1000oC as well as to HF below
300oC.
Sapphire is anisotropic hexagonal crystal. Its properties depend on crystallographic direction (relative to the optical C-axis). Large sized sapphire crystals up to 4 inches in diameter are available in
New Rise Optics. Our sapphire crystals are produced by two method——TGT and Czochraski for the highest optical and substrate quality.
Main
Properties
| Crystal
properties
|
| Crystal
Growth Method
|
|
| Maximum
Size
|
<Φ100mm
|
|
Optical
properties
|
| Transmission
Range
|
0.15~5.5
um
|
| Reflection
Loss, for two surfaces at 5 µm
|
14%
|
| dn/dt
(@633nm),
/K
|
13´10-6
|
| Refractive
Index
|
See
below
|
|
Wavelength
(um)
|
No
|
Ne
|
Wavelength
(um)
|
No
|
Ne
|
|
0.185
|
|
|
0.800
|
1.76013
|
1.7522
|
|
0.193
|
1.92879
|
1.91743
|
1.064
|
1.75449
|
1.74663
|
|
0.213
|
1.88903
|
1.87839
|
1.320
|
1.75009
|
1.74227
|
|
0.226
|
1.87017
|
1.85991
|
1.550
|
1.74618
|
1.73838
|
|
0.248
|
1.84696
|
1.83719
|
2.010
|
1.73748
|
1.72973
|
|
0.266
|
1.83304
|
1.82358
|
2.703
|
1.71900
|
1.71100
|
|
0.280
|
1.82437
|
1.81509
|
3.333
|
1.70100
|
1.69300
|
|
0.308
|
1.81096
|
1.80198
|
3.704
|
1.68700
|
1.67900
|
|
0.355
|
1.79598
|
1.78732
|
4.000
|
1.67400
|
1.66600
|
|
0.488
|
1.7753
|
1.76711
|
4.348
|
1.65800
|
1.65000
|
|
0.532
|
1.7717
|
1.76355
|
4.762
|
1.63600
|
1.62800
|
|
0.633
|
1.7659
|
1.75787
|
5.000
|
1.62300
|
1.61500
|
|
0.780
|
1.76068
|
1.75274
|
5.263
|
1.60700
|
1.59900
|
|
Transmission
Curve
|
See
below
|
|
|
|
Crystallographic
properties
|
| Syngony
|
Hexagonal
System
|
| Crystal
Form
|
Poly
or Single Crystal
|
| Lattice
Constant, Å
|
a=4.785,
c=12.991
|
| Cleavability
|
<1011>,
<1012>, imperfect
|
|
Physical
properties
|
| Density,
at 20 оС
|
3.98
g/cm3
|
| Hardness,
Mohs
|
9
|
Dielectric
Constant 102-108 Hz at 298 K
Parallel to c-axis (//)
Perpendicular to c-axis (— )
|
10.55
8.6
|
| Melting
point,
оС
|
2042
|
Thermal
Conductivity, W/m·K
at at 300 K
Parallel to c-axis (//)
Perpendicular to c-axis (— )
|
35.1
33.0
|
Thermal
Expansion, 1/K at 298 K
Parallel to c-axis (//)
Perpendicular to c-axis (— )
|
5.6 × 10-6
5.0 × 10-6
|
| Specific
Heat Capacity, W×s/g/k
|
0.418
|
| Bandgap,
eV
|
9.9
|
| Knoop
Hardness, kg/mm2
|
1370
|
| Young's
Modulus, Gpa
|
335
|
| Shear
Modulus, GPa
|
148
|
| Bulk
Modulus, Gpa at 273 K
|
240
|
| Poisson's
Ratio
|
0.25
|
| Elastic
Coefficient
|
C11=496,
C12=164, C13=115, C33=498, C44=148
|
| Apparent
Elastic Limit
|
275
MPa (13000psi)
|
|
Chemical
properties
|
|
Solubility
in water at 20 оС, g/100cm3
|
98×10-6
|
| Solubility
in acids
|
Soluble
|
| Molecular
Weight
|
101.94
|
Main Applications
These properties encourage the use of Sapphire in aggressive environments where reliability, optical transmission or strength is required. It is have the following wide applications in the range from the vacuum ultraviolet to the near infrared:
Optical applications:
- Illumination windows
- Sapphire light guides
- LCD projector windows
- Optical components such as lenses, prisms, other laser and infrared optics
Medical applications:
- Surgical tips
- Endoscope lenses
Analytical applications:
- Used in very high-pressure applications in replacement of glass or quart tubes in NMR
- Sapphire replaces quartz to improve durability and reduce contamination in mass
spectroscope
Aerospace applications:
- Windows for sensors
- Infrared Countermeasure lamps
Electronic applications:
Sapphire substrate with different orientation has different applications:
- (0001) Basal Plane Sapphire Substrate:
● Epitaxial Gallium Nitride chip for blue LED
● IR detector
- (-1 1 0 2) R-Plane Sapphire Substrate:
● GaAs wafer carriers
● Microwave IC
● SOS (Silicon on Sapphire)- High Speed IC
● Pressure Transducer
- (1 -1 2 0) A Plane Sapphire Substrate:
● The growth of high Te superconductors
General Specifications
| Optical
Sapphire Windows
|
| Parameters
|
Commercial
grade
|
Precision
grade
|
| Orientation
|
C-axis±1o,
C-axis±0.5o, or any orientation as
customers’ request
|
| Diameter
Tolerance
|
+0/-0.10mm
|
| Thickness
Tolerance |
±0.10mm
|
| Clear
Aperture
|
>Central
90% of diameter
|
| Surface
Quality |
60-40
S/D
|
40-20
S/D
|
| Parallelism
|
3~5
arc min
|
1
arc min
|
| Surface
Flatness
|
1λ
per 25mm
|
λ/4
|
| Chamfer
|
0.15~0.35mm×45°
face
width × 45°±15°
|
| Coating
|
Coatings
are available upon request
|
| Epi-ready
Sapphire Substrates
|
| Parameters
|
Value
|
| Diameter
|
50.8±0.05mm
|
76.2±0.05mm
|
| Thickness
|
330-430±50μ
|
380-480±50μ
|
| Orientation
|
C
(0001) ±0.2o
A
(1120) ±0.2o
R
(1102) ±0.2o
|
C
(0001) ±0.2o
A
(1120) ±0.2o
R
(1102) ±0.2o
|
| TTV
and Bow
|
<20u
m
|
<25um
|
| Front
Surface |
Epi
polished
|
Epi
polished
|
| Back
Side
|
Lapped
or polished
|
Lapped
or polished
|
| Flatness
|
<5um
|
<5um
|
| Roughness
(Ra) |
<0.5um
|
<0.8um
|
|