All circuit designs begin with the proper choice of substrate. Factors such as dielectric constant, loss tangent, thermal dissipation and cost all factor into the proper choice of material. We offer our services on all substrate materials — Al
2O
3 (Alumina — 99.6% as-fired or polished), BeO, AlN, Fused Silica and Barium Titanate all provide various properties of interest to the designer.
Common Substrates and Properties
| Material |
Surface Finish
& Roughness |
inch/inch |
g/cm3 |
KX10-3 |
10-6/°C |
(@25°C)
w/m°K |
kV/
mm |
Ωcm |
1MHz/
10GHz |
1MHz/
10GHz |
| A |
B |
C |
D |
E |
F |
G |
H |
I |
| Alumina |
Fired
|
± 3µ"
|
± 0.003
|
3.88
|
90
|
7-8.3
|
~35
|
~23
|
<1014
|
9.9/
9.6
|
.001/
.002
|
|
Pol.
|
< 1µ"
|
0.0005
|
|
Lapped
|
12"-20µ"
|
0.001
|
3.30
|
59
|
4.6
|
170
|
~15
|
<1013
|
8.5-9.2
/na
|
.004/
na
|
|
Pol.
|
< 2µ"
|
0.0005
|
|
Pol.
|
60/40
|
0.0005
|
2.20
|
25
|
0.55
|
1.38
|
30
|
<1010
|
3.82/
na
|
-
|
|
Lapped
|
7 -12µ"
|
0.0005
|
|
Pol.
|
<1µ"
|
0.0005
|
3.97
|
60
|
5.3
|
~40
|
-
|
<1017
|
9.3*-11.4
/na
|
.00086-.
0003*
|
|
Lapped
|
10"-20µ"
|
0.0005
|
|
Pol.
|
10µ
|
0.001
|
-
|
-
|
-
|
-
|
-
|
< 1017
|
11.3/
15.4
|
.0002-
.0015
|
*Varies with crystal orientation. A Plane / C Plane
A: Camber B: Density C: Flexural Strength D: Thermal Expansion E: Thermal Conductivity
F: Dielectric Strength G: Volume Resistivity H: Dielectric Constant I: Loss Tangent
|
Materials Properties Chart
|
Chemical Composition
|
|
AI2O3
|
AI2O3
|
AIN
|
SiO2
|
AI2O3
|
—
|
—
|
|
Purity
|
%
|
99.6
|
99.6
|
98
|
100
|
100
|
—
|
—
|
|
Color
|
|
White
|
White
|
Tan
|
Transparent
|
Transparent
|
Cream
|
Gray
|
|
Nominal Density
|
g/cm3
|
3.87
|
3.87
|
3.28
|
2.2
|
3.97
|
—
|
—
|
|
Surface Finish (Polished)
|
μ-inches
|
<1.0
|
n/a
|
<2.0
|
60/40 Optical
|
<1.0μ-inch CLA
|
<3.0
|
<16.0
|
|
Surface Finish (As fired)
|
μ-inches
|
n/a
|
2-3
|
n/a
|
n/a
|
n/a
|
n/a
|
n/a
|
|
Camber
|
inch/inch
|
.0003/.0005
|
.002
|
.0003/.0005
|
.0003/.0005
|
.0003/.0005
|
—
|
—
|
|
Thickness
|
inches
|
0.004-.040*
|
0.005-0.025*
|
0.004-0.100*
|
0.004-0.080*
|
0.004-0.050*
|
0.005-0.025*
|
0.010-0.025*
|
|
Thickness Tolerance
|
inches
|
±0.0005
|
±0.001*
|
±0.0005
|
±0.0005
|
±0.0005
|
±0.0005
|
±0.0005
|
|
Process Sizes
|
inches
|
|
|
|
|
|
|
|
|
(L/W)
|
1.0/4.5
|
1.0/6.0
|
1.0/2.25
|
1.0/2.25
|
1.0/2.25
|
1.0/2.25
|
1.0/2.25
|
|
|
Coefficient of Thermal Expansion (CTE)
|
10-6
|
7.0-8.3
(25-1000°C)
|
7.0-8.3
(25-1000°C)
|
4.6
(25-300°C)
|
0.55
(20-320°C)
|
A plane @
25°C-5.3
|
—
|
—
|
|
Thermal Conductivity
|
Watts/m°K
|
26.9
|
26.9
|
170
|
n/a
|
n/a
|
—
|
—
|
|
Dielectric Constant
|
@1 MHz
|
9.9±0.1
|
9.9±0.1
|
8.6
|
3.826
|
11.5/9.3†
|
36–180
|
14.5–17.6
|
|
Dielectric Constant
|
@4 MHz
|
9.9
|
9.9
|
—
|
—
|
—
|
—
|
—
|
|
Dielectric Constant
|
@10 MHz
|
9.7
|
9.7
|
—
|
—
|
—
|
—
|
—
|
|
Dissipation Factor (Loss Tangent)
|
@1 MHz
|
0.0001
|
0.0001
|
0.001
|
0.000015
|
.00086/.0003†
|
—
|
—
|
|
Dissipation Factor (Loss Tangent)
|
@10 MHz
|
0.0002
|
0.0002
|
—
|
—
|
—
|
—
|
—
|
|
Q
|
@1 GHz
|
5000
|
5000
|
5000
|
—
|
—
|
—
|
—
|
|
Hardness
|
Rockwell
|
87
|
87
|
n/a
|
7 Mohs
|
1800/2200A
Knoop
|
—
|
—
|
|
Flexural Strength
|
K(10-3) lbs/sq.in.
|
90
|
90
|
59
(4 pt. bend)
|
25
|
60
|
—
|
—
|
|
Compressive Strength
|
M(10-3) lbs/sq.in.
|
54
|
54
|
n/a
|
161
|
350
|
—
|
—
|
|
Grain Size
|
um (microns)
|
<1.0
|
<1.0
|
5-7
|
Amorphous
|
Single Crystal
|
—
|
—
|
• Additional thicknesses and tolerances available upon request
† Value varies with orientation ("A" plane / "C" plane)
|