Alumina Oxide Treatment Effect on Bias Resistance

BZ1 W277 P19 Untreated (Grounds Tied)BZ1 W230 P7 Alumina Treated(Grounds Not Tied)

Bias Voltage (V)Average Rbias

(Ohms)

5 4.31E+10

50 2.81E+10

100 2.99E+10

150 3.67E+10

200 9.83E+10

250 2.34E+10

Bias Voltage (V) Rbias (Ohms)

5 2.31E+04

50 7.81E+04

100 5.00E+05

150 1.12E+06

200 1.12E+06

250 1.13E+06

Tests were done by holding 3 neighboring strips at a varied potential and observing the current on the center strip while biasing the detecting via its backplane. For the untreated device, Rbiaswas equal to the inverse of the slope of the line fit to the data of the voltage and center strip’scurrent. For the treated device, no linear relationship was found, so Rbias was calculatedbetween each strip voltage step and then averaging all values for each biasing voltage.

0 50 100 150 200 250 3001E+04

1E+06

1E+08

1E+10

1E+12Alumina Treatment Effect on Bias Resistance

Untreated Grounds Not Tied

Treated Grounds Not Tied

Untreated Grounds Tied

Bias Voltage (V)

Bias

Res

ista

nce

(Ohm

s)

Measuring Bias Resistance

0 50 100 150 200 250 3001.00E+04

1.00E+05

1.00E+06

1.00E+07Difference in Bias Resistance Calculated Based on Tying Grounds

Grounds Tied (Long Int. Time)Grounds Not Tied (Long Int. Time)

Bias Voltage (V)

Bias

Res

ista

nce

(Ohm

s)

0 50 100 150 200 250 3001.00E+04

1.00E+05

1.00E+06

1.00E+07

Integration Time Effect on Measuring Bias Resistance (Grounds Tied)W277 P19 Strip 40 Untreated

Short Integration TimeMedium Integration TimeLong Integration Time

Bias Voltage (V)

Bias

Res

ista

nce

(Ohm

s)

Circuit Used to Measure Bias Resistance

All 3 strips on the DC pads were held at the same potential.Ground of the power supply shouldbe connected to grounds of theparameter analyzer.

0 50 100 150 200 250 3001.00E+05

1.00E+06

1.00E+07

1.00E+08

1.00E+09

1.00E+10

1.00E+11

1.00E+12

W230 P7 Interstrip Resistance Before and After Alumina Treatment(P-Spray 2e12)

Post Treatment

Pretreatment

Bias Voltage (V)

Inte

rstr

ip R

esis

tanc

e (O

hms)

Difference in Interstrip Resistance Calculated Based on Probe Configurations

Bias Voltage (V)Rint (Ohms), Center Strip

Held at Ground

Rint (Ohms), Neighboring Strips Held at Ground (Ignoring Rbias term)

5 4.47E+08 2.49E+08

50 5.25E+08 5.56E+08

100 5.38E+08 4.08E+08

150 4.99E+08 5.33E+08

200 4.56E+08 4.94E+08

250 4.27E+08 4.56E+08

W230 P7 Post Alumina Treatment Rint, small difference in calculation based on probe configurations (not

accounting for bias resistance)

0 50 100 150 200 2501.00E+06

1.00E+07

1.00E+08

1.00E+09

Difference in Interstrip Resistance Calculated Based on Testing Method

Center strip held at GND

Neighbor strips held at GND

Bias Voltage (V)

Inte

rstr

ip R

esist

ance

(Ohm

s)

Circuit Used to Measure Interstrip Resistance

The different probe configurations are:1. Center strip held at ground, its neighborsheld at varying potentials.2. Center strip held at varying potential,its neighbors held at ground.In both cases, the 3 probes are connected toThe parameter analyzer.

Interstrip Resistance Calculation

• Center strip held at ground, varying potential applied to neighboring strips:

dICenter/dVCenter=2/RInterstrip

• Neighboring strips held at ground, varying potential applied to center strip:

dICenter/dVCenter=

(-2/RInterstrip)-(1/RBias)

Leakage current of the detector suddenly increased and stayed higher, 25uA at 312V

0 50 100 150 200 250 300 350 4001.00E-10

1.00E-09

1.00E-08

1.00E-07

1.00E-06

1.00E-05

1.00E-04

ATLAS07A BZ1-P07 W230 Simple IV Log Scale

Post Treatment 2/5/13

Pre Treatment 5/3/12

Post Treatment 4/9/13

Bias Voltage (V)

Leak

age

Curr

ent (

A)

W230 P7 Post Alumina Treatment Bias Resistors

W281 P7 Bias Resistors Post Alumina Treatment

W278 P7 Bias Resistors Post Alumina Treatment

Untreated BZ1 Bias Resistors

Strip numbers missing only on W278 P7 after alumina treatment