Biomedical Engineering Reference
In-Depth Information
TABLE 8.3
Comparison of Different Types of Deposition Methods
CVDand
MOCVD
Laser
Ablation
Sputtering
MBE
Sol-Gel
FCVA
Deposition
rate
medium
(a few nm/s)
Low (0.2 to a
few nm/s)
Low (0.1 to
0.4 nm/s)
Very low
High
High
(0.2-15 nm/s
Compatibility
with MEMS
processing
Good
OK
Poor
Poor
Good
Poor
Temperature
25 to 400°C
300 to 900°C
200 to 600°C
300 to
800°C
25 to
100°C
Below 400°C
Quality
Good
Good
Good
Excellent
Poor
Good
Cost
Slightly cost
Medium
Medium
High
Cheap
Medium
Deposition
size
Large area
Large area
Small size
Medium
Large area
Small size
technology (Dang et al., 2007). In this section, we will focus on the texture and acoustic
wave properties of sputtered ZnO films (Table 8.4).
The microstructure, texture, and PE properties of the sputtered ZnO films are normally
affected by sputtering conditions such as plasma power, gas pressure, substrate, tempera-
ture, and film thickness. During sputtering, the energetic ion bombardment has signifi-
cant effects on the stoichiometry, size, shape and orientation of ZnO crystals, intrinsic
stress, defects, electrical and optical properties, as well as the surface and cross-section
TABLE 8.4
Summary of Velocity of ZnO Films on Different Substrates
Lattice
Difference
(%)
Temperature
Expansion
Coeficient(10
−6
K
−1
)
Substrate
Materials
Substrate
Materials
Structure
Velocity(m/s)
ZnO
ZnO
HCP
2724
2.9 (4.751)
ZnO/Si
Si (111)
Cubic
41.3
2653
3
ZnO/Pt
Pt (111)
Cubic
1.8
2684
8.8
ZnO/Au
Au (111)
Cubic
2.5
14
ZnO/SiO
2
Quartz
4200
13.2 (a)/7.1c
Sapphire
Al
2
O
3
(0001)
HCP
31.8
4000-5750
7.3 (18.1)
ZnO/LiNbO
3
LiNbO
3
(0001)
HCP
14.8 (4.1)
ZnO/sapphire
sapphire (0001)
HCP
31.8
8.4 (5.3)
ZnO/GaN
GaN
HCP
1.8
3.17
ZnO/AlN
AlN
HCP
4.1
4522,
5.3 (4.1)
ZnO/DLC
DLC
Amorphous
5000-7000
ZnO/
Nanocrystalline
diamond
8500
1.18
ZnO/Diamond
Diamond (111)
Cubic
10,000-12,000
1.18
ZnO/AlN/
diamond
ZnO/AlN/
diamond
12,200
Note:
Most data are from SAW devices; data are only used for comparison, as velocity is related to thickness,
thus comparison of velocities is not meaningful unless film thickness is similar.
