nc 200 test data

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1. Deposition rate measurements

A quartz crystal monitor (at a distance of 100mm from the source aperture) was usedto measure the deposition rate of the clusters (note for Cu, 1Hz = 0.11).

The deposition rate was measured as a function of the magnetron power for variousAr flow rates and a set aggregation length of 205 mm.

0 50 100 150 200 250

0

50

100

150

200

Depositionrate(Hz/min)

Power (W)

Ar 25 sccm

Ar 20 sccm

Ar 15 sccm

Ar 10 sccm

Figure 2: Deposition rate as a function of magnetron power for various flows

The deposition rate was measured as a function of the Ar gas flow rate for variousaggregation lengths and a fixed power of 25Watts.

0 5 10 15 20 25 30

0

20

40

60

80

100

120

140

160

Depositionrate(Hz/min)

Ar flow (sccm)

Distance 205 mm

Distance 195 mm

Distance 155 mm

Distance 85 mm

Figure 3: Deposition rate as a function of Ar gas flow rate for various aggregation lengths

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Note that the deposition rate drops at higher Ar flow and magnetron power. This isdue to the increased number of collisions between particles and thus a reduction in themean free path of the clusters.

2. Cluster mass measurements

Cluster mass with Ar flow rateThe Ar flow rate was varied for a fixed power and aggregation length. The resultingmass spectra (taken using the QMF200) are shown below of negatively charged Cuclusters.Power: 38W, Agg length: minimum, He: 0 sccm, Apertures 5mm inner, 4mm outer.

01x10

5

2x10

5

3x10

5

4x10

5

5x10

5

6x10

5

0

1

2

3

4

5

6

7

8

9Cu Mass Spectra with Ar Flow Rate

ClusterIonCurrent(x1010A)

Mass (a.m.u.)

10sccm

30sccm

50sccm

70sccm90sccm

Figure 4.

From these spectra the mean cluster mass can be plotted as a function of the Ar flow.This is shown below in figure 2.

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0 20 40 60 80 100

4.0x104

6.0x104

8.0x104

1.0x105

1.2x105

1.4x105

1.6x105

1.8x105

2.0x105

2.2x105

2.4x105

Relationship between mean cluster mass

and Ar gas flow for Cu clusters

ClusterMass(amu)

Ar Flow (sccm)

Figure 5

Cluster mass with He flow rateThe He flow rate was varied for a fixed power, aggregation length and Ar flow rate.The resulting mass spectra (taken using the QMF200) are shown below of negativelycharged Cu clusters.Power: 37W, Agg length: minimum, Ar: 20 sccm, Apertures 5mm inner, 4mm outer.

0 1x105

2x105

3x105

4x105

5x105

6x105

7x105

0

2

4

6

8

10


Cu mass spectra with He flow rate

Mass (a.m.u.)

0sccm

10sccm

30sccm

50sccm

70sccm

90sccm

Figure 6

From these spectra the mean cluster mass can be plotted as a function of the He flow.This is shown below in figure 4.

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0 20 40 60 80 100

6.0x104

8.0x104

1.0x105

1.2x105

1.4x105

1.6x105


and He flow for Cu clusters

ClusterMass(a.m.u.

)

He Flow (sccm)

Figure 7

Cluster mass with magnetron powerThe magnetron power was varied for a fixed aggregation length, Ar and He flowrates. The resulting mass spectra (taken using the QMF200) are shown below ofnegatively charged Cu clusters.Agg length: minimum, Ar: 40 sccm, He: 60sccm, Apertures 5mm inner, 4mm outer.

0.0 5.0x104

1.0x105

1.5x105

2.0x105

2.5x105

3.0x105

3.5x105

0

1

2

3

4

5

6

7


Cu mass spectra with power

Mass (a.m.u.)

35W

30W

25W

20W

15W

Figure 8

From these spectra the mean cluster mass can be plotted as a function of the power.This is shown below in figure 6.

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15 20 25 30 35 402x10

4

3x104

4x104

5x104

6x104

7x104

8x104

9x104


and power for Cu clusters

Mass(a.m.u.)

Power (Watts)

Figure 9

Cluster mass with aggregation lengthThe aggregation length was varied for a fixed power, Ar and He flow rates. Theresulting mass spectra (taken using the QMF200) are shown below of negatively

charged Cu clusters.Power: 35W, Ar: 15 sccm, He: 0sccm, Apertures 5mm inner, 4mm outer.

0 1x105

2x105

3x105

4x105

5x105

6x105

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0


Cu mass spectra with aggregation length

Cluster mass (a.m.u.)

65mm

95mm

125mm

155mm

Figure 10

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Large clusters

Large clusters can be acquired with the NC200U using high powers and relativelyhigh Ar gas flows. The graph below shows such a spectrum which goes beyond therange of the QMF200. These clusters are positively charged.Power : 95W, Ar flow: 65sccm, He:0, Aggregation length: maximum.

0.0 5.0x105

1.0x106

1.5x106

2.0x106

2.5x106

3.0x106

0.0

0.5

1.0

1.5

2.0

2.5

3.0Large Cu clusters from the NC200U source

IonCurre

nt(nA)

Mass (a.m.u.)

Figure 11

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Small clusters

Small clusters can be acquired with the NC200U using low powers and high He gasflows. The graph below shows spectra of negatively charged clusters for two differentHe flows. Individual cluster peaks can just be resolved.Power : 10W, Ar flow: 35sccm, He flow:110sccm, 90sccm Aggregation length:minimumQMF: f=100kHz, U/V =0.15, Sit=0, External Keitherly nanometer input.

0 200 400 600 800 1000 1200 1400 1600 1800

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

ClusterIonCurrent(x1

010A)

BA

Mass (a.m.u.)

110sccm He

90sccm He

Figure 12

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From the above graph the value of k (the correction factor) can be calculated. Thevalue k is used in the calculation of the mass:

M=7x107(kV/f2d2)

Where M is the mass, V is the AC voltage, f is the frequency and d is the diameter ofthe quadrupole poles.

On the graph the peaks A and B lie at 500amu and 793amu. There are five distinctpeaks between these peaks giving an average separation of 48.8amu. For Cu clustersthis value should be 63.5 (the atomic weight of Cu). The correction factor is therefore:

k= 63.5/48.8 = 1.30

This value is comparable with the result calculated by Baker et al1. (1.25) whodetermined the constant by using ionised Ar. The corrected mass spectrum is shown

in figure 10. The number of atoms per cluster has been added.

0 200 400 600 800 1000 1200 1400 1600 1800 2000

0.5

1.0

1.5


Mass (a.m.u.)

1716

15

14131211

10

9

8

7

6

110sccm He

90sccm He

Figure 13

1 S.H.Baker et al. Rev.Sci.Instrum. 68(4) p 1853, 1997.

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3. Other measurements

Beam size from cluster sourceThe beam diameter was measured for different aperture plate arrangements at adistance of 100mm.

-40 -30 -20 -10 0 10 20 30 40

0.0

0.2

0.4

0.6

0.8

1.0Red - 4mm inner, 5mm skimmer

Black - 4mm inner, 10mm skimmer

Blue - 8mm inner, 10mm skimmer

NC200U Beam profiles with different aperture

arrangements at a distance of 100mm

Depositionrate(normalised)

Distance (mm) Figure 14

nc 200 test data

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