Sergey Korjenevski KSU D0 RunIIb Silicon , Feb 6, 2003 1 out of 10

Measurements on L2 Test Structures

Sergey Korjenevski Christopher Borjas

Kansas State UniversityFebruary 6, 2003

D0 RunIIb Silicon

Sergey Korjenevski KSU D0 RunIIb Silicon , Feb 6, 2003 2 out of 10

Outline

Visual Inspection of L2 sensors Interstrip and coupling capacitance

on Test Structures Resistance on Test Structures

Interstrip Implant, Dielectric and Aluminum Rpoly on baby detector and on Array

New software and switching matrix Offset

Sergey Korjenevski KSU D0 RunIIb Silicon , Feb 6, 2003 3 out of 10

Visual inspection

Found broken implant

Sergey Korjenevski KSU D0 RunIIb Silicon , Feb 6, 2003 4 out of 10

Capacitance

• Interstrip capacitance measured on Test Structures• Consistent and within specs < 1.2 pF/cm at 1kHz

Interstrip capacitance

0.000

2.000

4.000

6.000

8.000

10.000

0 10 20 30 40

Vbias

C,

pF

1 kHz

5 kHz

10 kHz

Sergey Korjenevski KSU D0 RunIIb Silicon , Feb 6, 2003 5 out of 10

Coupling Capacitance

0.000

500.000

1000.000

1500.000

2000.000

2500.000

0 10 20 30 40

1kHz

100 Hz

• Coupling capacitance on Baby Detector with NO Rpoly• Does not depend on Vbias

Sergey Korjenevski KSU D0 RunIIb Silicon , Feb 6, 2003 6 out of 10

Coupling Capacitance Breakdown

• Coupling capacitance breaks down at about 200VCurrent / Capacitance vs Voltage

0

100

200

300

400

500

600

700

800

0 50 100 150 200 250

Voltage (V)

Cu

rre

nt

(nA

) /

Ca

pa

cit

an

ce

(p

F)

I, nA

C, pF

Sergey Korjenevski KSU D0 RunIIb Silicon , Feb 6, 2003 7 out of 10

Interstrip Resistance

• Interstrip Resistance drops to KOhms at about 2.5V• Same behavior even if the two strips not next one to another

Rint

0

1

2

3

4

5

6

7

8

0 0.5 1 1.5 2 2.5 3 3.5 4

Rint

Low current, high noisebut definitely a few GOhms

Sergey Korjenevski KSU D0 RunIIb Silicon , Feb 6, 2003 8 out of 10

Implant, Polysilicon, Dielectric

• R implant = 1.78 MOhm• R diel ~ 2GOhm• R Al ~ 1 KOhm

• Polysilicon: • on array 1.0 Mohm• on 2 DC int = 0.8 Mohm• on Bias to DC int = 0.73 Mohm• on 2 DC readout (assume Rimplant constant) from 0.5 Mohm down to negative• on Bias to DC readout (standard test) from 0.16 Mohm to negative• Interstrip resistance alternative test

• R(neighbor DCint to DCreadout) – R(far most DCint to Dcreadout)• about 1 MOhm

isolated strip

Sergey Korjenevski KSU D0 RunIIb Silicon , Feb 6, 2003 9 out of 10

Implant, Polysilicon, Dielectric

Array: Baby without Rpoly: Baby with Rpoly:

DC intermediate DC readout

Sergey Korjenevski KSU D0 RunIIb Silicon , Feb 6, 2003 10 out of 10

Last Slide

Visual inspection maybe performed before and after testing. For instance open strip detection could be confirmed visually.

Interstrip resistance drops from few Gohms to Kohms at 2.5V.

PolySi resistor value setup could be changed (use of DCint). Rpoly consistency test should probably stay.