Biomedical Engineering Reference
In-Depth Information
TABLE 16.2
Low-temperature (RT−100 °C) ALD processes.
Material
Precursor 1
Precursor 2
Temperature
References
Al
2
O
3
TMA
H
2
O
33 °C
13
Al
2
O
3
TMA
O
3
RT
14
Al
2
O
3
TMA
O
2
-plasma
RT
15
B
2
O
3
BBr
3
H
2
O
RT
16
CdS
Cd(CH
3
)
2
H
2
S
RT
17
HfO
2
Hf[N(Me
2
)]
4
H
2
O
90 °C
18
Pd
Pd(hfac)
2
H
2
80 °C
19
Pd
Pd(hfac)
2
H
2
-plasma
80 °C
20
Pt
MeCpPtMe
3
O
2
-plasma
+
H
2
100 °C
21
PtO
2
MeCpPtMe
3
O
2
-plasma
100 °C
21
SiO
2
Si(NCO)
4
H
2
O
RT
22
SiO
2
SiCl
4
H
2
O
RT
a
23
SnO
2
TDMASn
H
2
O
2
50 °C
24
Ta
2
O
5
TaCl
5
,
H
2
O
80 °C
25
Ta
2
O
5
Ta[N(CH
3
)
2
]
5
O
2
-plasma
100 °C
26
Ta
TaCl
5
H-plasma
RT
27
Ti
TiCl
4
H-plasma
RT
28
TiO
2
Ti[OCH(CH
3
)]
4
H
2
O
35 °C
29
TiO
2
TiCl
4
H
2
O
100 °C
30
V
2
O
5
VO(OC
3
H
9
)
3
O
2
90 °C
31
ZnO
Zn(CH
2
CH
3
)
2
H
2
O
60 °C
32
ZnO
Zn(CH
2
CH
3
)
2
H
2
O
2
RT
33
ZrO
2
Zr(N(CH
3
)
2
)
4
)
2
H
2
O
80 °C
34
a
Wth pyridine as catalyst.
corresponding machinery is being indepen-
dently developed by several vendors.
available that allow a complete recovery of the
excess precursors used. Both cost and waste are
serious issues for many industrial applications.
16.1.4.4 Cost of the Precursors
The remaining drawbacks relate to the costs of
the precursors, which depend on the target mate-
rial and often are very high. The unavoidable
waste of the precursors even enhances the cost
factor: The precursors are injected in an excess
dose to saturate the substrate surface. The excess
is usually purged and lost. Optimized processing
parameters can reduce the waste to a great extent,
but there are no efficient commercial solutions
16.2 APPLICATION OF ALD TO
BIOMATERIALS
As described in Section
16.1
, ALD is a technology
formulated to produce devices such as displays.
With that origin, it is axiomatic that the research
and development on and with ALD mainly affect
technological fields. The use of substrates with
