Electrical measurements of sputtered NiCr on grid spacers (GS2mm)

07-11-2011

Dean Walters, Anil Mane Guy Harris, Jeff Elam

Objective

To deposit NiCr layer(150-200nm/side) on grid spacers for better electrical contact.

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As received After NiCr coating

• Appearance of NiCr coated grid looks good

Photograph after NiCr electrode

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NiCr

Glass

• Grid edges are sharp but much better than previous vender• Overall deposition looks great.

Thickness values based on Resistance on the grid spacer

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Considered Bulk rho of NiCr

Pt # Resistance (ohm) Thickness (nm)1 62 5.342 22 15.043 64 5.174 15 22.075 15 22.076 14 23.647 19 17.428 17 19.479 9 36.78

10 11 30.0911 18 18.3912 15 22.0713 12 27.5814 14 23.6415 57 5.8116 20 16.5517 68 4.87

1 2 3

4 5 6

7 8 9 10 11

12 13 14

15 16 17

• Thickness non-uniformity on the grid spacer• We need to improve the Thickness NU and then we can target thickness= 50nm• I think 50nm uniform thickness of NiCr will be sufficient for good electrical contact?

Similar number and trend observed for other side of the grid spacer

Rings of Equal Thickness (nm) – Anil’s data

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X Y Thk1 0 8 4.92 8 8 53 8 0 5.34 0 0 5.85 8 4 156 0 4 16.57 4 0 17.48 4 2 19.59 2 2 22

10 6 2 22.111 6 4 22.112 2 6 23.613 6 6 23.614 2 4 27.615 4 6 30.116 4 4 36.8

0

1

2

3

4

5

6

7

8

9

0 2 4 6 8 10

16

22

5

30

3D Plot and Diagonal Cut

Making a cut through the data using both diagonals a cross section plot was made.

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02

46

8

05

10152025303540

02

46

8

02468

0 2 4 6 8 10 120

5

10

15

20

25

30

35

40

f(x) = 0.03192791 x⁴ − 0.73614619 x³ + 4.36316181 x² − 1.43009569 x + 5.81R² = 1

Series1Polynomial (Series1)Series3

All measurements18.6 Average9.21 Std Dev

Four groups of glass samples were coated while being taped onto the surface of the tooling.They were in locations 4, 12, 6, 14 for each set.

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(0,8) (4,8) (8,8)

(0,0) (4,0) (8,0)

1 2 3

4 5 6

7 8 9 10 11

12 13 14

15 16 17

Sample ID

Sheet resistance Thickness from

Rs ohm/sqbulk NiCr resistivity

(nm)

A 20.7 67.6B 24.7 56.7C 22.8 61.3D 25.9 54.1E 14.6 95.6F 16.6 84.4G 17.6 79.6H 18.4 75.9I 10.6 132J 11.6 121.1K 12.1 115.7L 10.8 129.8M 22.1 63.4N 22.5 62.3O 21.6 64.9

Grp 4

Grp 2

Grp 3

QCM=30

Avg 59.93Std Dev 5.92

Avg 83.88Std Dev 8.56

Avg 124.65Std Dev 7.60

Avg 63.53Std Dev 1.31

QCM=20

Grp 1

QCM=40

QCM=20

Conclusion

Grid Data – Average of the data was 18 nm– Maximum of data was 36.8 nm

Data from Flat Glass Samples– Average of Group #1 is 60 nm– Average of Group #2 is 84 nm– Average of Group #3 is 125 nm

The setup for Group #1 (& #4) were the same as the grid data. There is nearly a 4X difference between those averages and the is a 2X difference

the maximum point and the samples.

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