SETs Deposition
Alvar Rodríguez, Simranjeet Singh
UCF, 2014
First layer Development:
Use first layer without gate (1st in UCF SET MASK 2)
a. Spin on LOR resist then bake on hotplate for 5 minutes at 175°C.
b. Spin on Shipley resist then back on hotplate for 2 minutes at 120°C.
LOR 3A (B)
2s at 500rpm / 30s at 3000rpm / 2s at 0rpm
Shipley S1813 (A)
2s at 500rpm / 30s at 5000rpm / 2s at 0rpm
1. Place wafer in beaker of CD-26 for 45 seconds, quickly place in DI water.
2. Spray wafer with DI water then blow dry.
3. Check patterning with microscope, if the etch and color is good place it at 130°
C for 5 minutes, then 1 minute in CD-26 followed by DI and Nitrogen blow dry.
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First layer Deposition:
Before this deposition O2 plasma cleaning de sample:
SCCM
12
Power
50 W
Pressure
200 mTorr
Time
10 s
Deposition in the shared facility clean room e-beam deposition
Density
Z-ratio
Tooling Factor
Deposition Rate
Thickness
Current
i.
Ti
4.5 g/cm3
0.628
170 %
1 Å/s
5 nm
~30 mA
Pd
12 g/cm3
0.357
170 %
0.4 Å/s
10 nm
~40 mA
For lifting off, place sample in PG Remover for about an hour
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Second layer Development:
a. Spin on LOR resist then bake on hotplate for 5 minutes at 175°C.
b. Spin on Shipley resist then back on hotplate for 2 minutes at 120°C.
LOR 3A (B)
2s at 500rpm / 30s at 3000rpm / 2s at 0rpm
Shipley S1813 (A)
2s at 500rpm / 30s at 5000rpm / 2s at 0rpm
1. Place wafer in beaker of CD-26 for 45 seconds, quickly place in DI water.
2. Spray wafer with DI water then blow dry.
3. Check patterning with microscope, if the etch and color is good place it at 130°
C for 5 minutes, then 1 minute in CD-26 followed by DI and Nitrogen blow dry.
Page 3 of 11
Second layer Deposition:
Before this deposition O2 plasma cleaning de sample:
SCCM
12
Power
50 W
Pressure
200 mTorr
Time
10 s
~80 nm on AFM (Deposition in the shared facility clean room e-beam deposition)
Density
Z-ratio
Tooling Factor
Deposition Rate
Thickness
Current
i.
Ti
4.5 g/cm3
0.628
170 %
1 Å/s
10 nm
~30 mA
Pd
12 g/cm3
0.357
170 %
1.4 Å/s
70 nm
~50 mA
For lifting off, place sample in PG Remover for about an hour
Page 4 of 11
Third layer Development:
Use the wider gates (IV in UCF ’11 SET Mask)
a. Spin on LOR resist then bake on hotplate for 5 minutes at 175°C.
b. Spin on Shipley resist then back on hotplate for 2 minutes at 120°C.
LOR 3A (B)
2s at 500rpm / 30s at 3000rpm / 2s at 0rpm
Shipley S1813 (A)
2s at 500rpm / 30s at 5000rpm / 2s at 0rpm
1. Place wafer in beaker of CD-26 for 45 seconds, quickly place in DI water.
2. Spray wafer with DI water then blow dry.
3. Check patterning with microscope, if the etch and color is good place it at 130°
C for 5 minutes, then 1 minute in CD-26 followed by DI and Nitrogen blow dry.
Page 5 of 11
Third layer Deposition:
Deposition in the shared facility clean room e-beam deposition
Before this deposition O2 plasma cleaning de sample:
SCCM
12
Power
50 W
Density
Z-ratio
Tooling Factor
Deposition Rate
Thickness
Current
Pressure
200 mTorr
Time
10 s
Al
2.7 g/cm3
1.08
160 %
0.6 Å/s
35 nm
~200 mA
Evaporate 10nm before opening the shutter for removing the Al2O3 first.
i.
For the Al layer place the sample in Acetone at Room Temperature for about 1
hour, spray with acetone for helping the lift off, then 5 min in PG and then DI
water.
Resistance Gates:
~ 400 Ω
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Fourth layer Development (Nanowires):
a.
b.
c.
d.
e.
Spin on MMA resist.
Bake for 5 minutes at 175°C.
Spin on PMMA resist.
Bake for 5 minutes at 175°C.
Take it to CREOL
MMA (8.5) EL 6 (E)
2s at 500 rpm / 60s at 4000 rpm / 2s at 0 rpm
950 PMMA C 2 (F)
2s at 500 rpm / 60s at 6000 rpm / 2s at 0 rpm
1. Develop sample in 3 IPA : 1 MIBK for 45 seconds.
2. Rinse with IPA and blow dry.
3. Check patterning under microscope if necessary develop a bit more.
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Fourth layer Deposition (Nanowires):
Deposition in the shared facility clean room e-beam deposition
Density
Z-ratio
Tooling Factor
Deposition Rate
Thickness
Current
i.
ii.
iii.
iv.
Au
19.3 g/cm3
0.381
175 %
1.5 Å/s
17 nm
~ 50 mA
Place sample at Room Temperature Acetone for about 1h.
Don’t rush or the nano-wires will be gone!
If it still doesn’t come off try spraying gently with Acetone.
Blow dry with a very light stream of Nitrogen gas.
Resistance Nano-Wires:
~ inf Ω
Resistance Gates:
~ 400 Ω
If Gates don’t work after Nano-wire deposition:
In Probe Station measure the gate’s resistance on top of gate’s ends
(sometimes you will need to scratch them a little bit) and suddenly it will start
measuring resistance.
Page 8 of 11
Fifth layer Development (Nanowires):
a.
b.
c.
d.
e.
Spin on MMA resist.
Bake for 5 minutes at 175°C.
Spin on PMMA resist.
Bake for 5 minutes at 175°C.
Take it to CREOL
MMA (8.5) EL 6
2s at 500 rpm / 60s at 4000 rpm / 2s at 0 rpm
950 PMMA C 2
2s at 500 rpm / 60s at 6000 rpm / 2s at 0 rpm
1. Develop sample in 3 IPA : 1 MIBK for 45 seconds.
2. Rinse with IPA and blow dry.
3. Check patterning under microscope if necessary develop a bit more.
Page 9 of 11
Fifth layer Deposition (Nanowires):
Deposition in the shared facility clean room e-beam deposition). This evaporation is
divided in two steps of 25 nm where the current is driven to zero in between the
steps. This layer needs to be 5 to 10 nm thicker than the Gate.
Density
Z-ratio
Tooling Factor
Deposition Rate
Thickness
Current
i.
ii.
iii.
iv.
Au
19.3 g/cm3
0.381
175 %
1.5 Å/s
50 nm
~ 50 mA
Place sample at Room Temperature Acetone for about 1h.
Don’t rush or the nano-wires will be gone!
If it still doesn’t come off try spraying gently with Acetone.
Blow dry with a very light stream of Nitrogen gas.
This layer can also be fabricated with Pd obtaining the same results:
Density
Z-ratio
Tooling Factor
Deposition Rate
Thickness
Current
Pd
12 g/cm3
0.357
170 %
1.4 Å/s
50 nm
~40 mA
Page 10 of 11
Resistance Nano-Wires:
~ 90 Ω
Resistance Gates:
~ 400 Ω
If Gates don’t work after Nano-wire deposition:
In Probe Station measure the gate’s resistance on top of gate’s ends
(sometimes you will need to scratch them a little bit) and suddenly it will start
measuring resistance.
Page 11 of 11