HPK L1 teststructures

•HPK L1 half moon teststructure

•corresponding to main chips 6,7

•Results on Diode C-V Coupling capacitors polysilicon arrays Strip capacitances MOS

R. Bernhard, F. LehnerU Zurich4/3/03

HPK L1 teststructures

• depletion voltage of diode ~110V

• Corresponding sensor (HPK-L1 #6,7) depletion voltages: 150V (HPK) 130V (KSU), 110V (FNAL) N.B. depletion voltage of segmented strip detector is ~5-10%

higher than planar diode

C-V L1 diode teststructure

1.00E+031.50E+032.00E+032.50E+033.00E+033.50E+034.00E+034.50E+03

20 40 60 80 100 120 140 160 180

bias (V)

1/C

2 (p

F-2

) 10 kHz

100kHz

500kHz

1 MHz

HPK L1 teststructures

•coupling capacitor test structure

•same length than on sensor: 7.74 cm

•low frequency limit: 115 pF => 14.8 pF/cm (in specs)

coupling capacitor L1 teststructure

0

20

40

60

80

100

120

0.1 1 10 100 1000 10000

frequency (kHz)

C (

pF

)

CC1

CC2

CC3

CC4

HPK L1 teststructures

•CC breakdown ~220-230 V

•similar to HPK-L2

coupling capacitor breakdown

-5.00E-06

-4.00E-06

-3.00E-06

-2.00E-06

-1.00E-06

-1.00E-21

1.00E-06

0 50 100 150 200 250 300

voltage (V)

I (A

)

CC1

CC2

CC3

HPK L1 teststructures

• Aluminum trace teststructure (meander-like)

• length 60 mm

• resistance: 35 Ohm/cm (spec: 30 Ohm/cm)

• HPK-L2: 16 Ohm/cm, smaller due to wider Al traces

Aluminium trace LW6000R=210Ohm, length=6 cm

R/cm = 35 Ohm/cm

-4.E-04

-2.E-04

0.E+00

2.E-04

4.E-04

-0.06 -0.04 -0.02 0.00 0.02 0.04 0.06

U (V)

I (A

)

HPK L1 teststructures

•p+ implant structure

•130 kOhm/cm (on HPK-L2: 104 kOhm/cm)

p-implantR=2605 Ohm, length=0.02 cm

R/cm=130kOhm/cm

-3.E-04

-2.E-04

-1.E-04

0.E+00

1.E-04

2.E-04

3.E-04

-0.60 -0.40 -0.20 0.00 0.20 0.40 0.60

U (V)

I (A

)

HPK L1 teststructures

•numerous polyresistor structures

•different arrays: PS0, PS10, PS20, PS30 and PSH0 – PSH30

•What is the difference? polysilicon material? Processing? doping?

HPK L1 teststructures

• linearity from in range from –5V to +5V given for PS-30 and PS-20 resistor array

• PS-10 and PS-0 have breakdown at ±2V

• in linear region all resistors measured to be 1.05 ± 0.01 Mohm

PSn30

-6.00E-06-4.00E-06-2.00E-060.00E+002.00E-064.00E-066.00E-068.00E-06

-5 -4 -3 -2 -1 0 1 2 3 4 5

U (V)

I (A

)

PS30_1

PS30_3

PSH30_1

PSH30_2

PSH30_3

PSH30_long_1

PSH30_long_3

PSH30_long_5

PSn20

-6.00E-06-4.00E-06-2.00E-060.00E+002.00E-064.00E-066.00E-068.00E-06

-5 -4 -3 -2 -1 0 1 2 3 4 5

U (V)

I (A

)

PS20_1

PS20_3

PSH20_1

PSH20_3

PSH20_long_3

PSH20_long_5

PSn10

-6.00E-06-4.00E-06-2.00E-060.00E+002.00E-064.00E-066.00E-068.00E-06

-5 -4 -3 -2 -1 0 1 2 3 4 5

U (V)

I (A

)

PS10

PSH10_1

PSH10_3

PSH10_long1

PSH10_long2

PSH10_long4

PS-10

-6.00E-06-4.00E-06-2.00E-060.00E+002.00E-064.00E-066.00E-068.00E-06

-5 -4 -3 -2 -1 0 1 2 3 4 5

U (V)

I (A

)

PSH0_1

PSH0_2

PSH0_long_1

PSH0_long_4

HPK L1 teststructures

• Baby detector w/ polysilicon resistors

• R_poly: 0.7 ± 10% Mohm

• R_poly + R_implant: 1.5 ± 10% Mohm implant alone: 130kOhm/cm

1MOhm implant for 7.7 cm strip not fully consistent !

polysilicon on babydetector

-1.50E-05

-1.00E-05

-5.00E-06

0.00E+00

5.00E-06

1.00E-05

-5 -4 -3 -2 -1 0 1 2 3 4 5

U (V)

I (A

)

poly strip 1

poly strip 2

poly strip 3

poly strip 4

polysilicon+implant resistor on L1 babydetector

-3.00E-06

-2.00E-06

-1.00E-06

0.00E+00

1.00E-06

2.00E-06

3.00E-06

-3 -2 -1 0 1 2 3

U (V)

I (A

)

Series1

Series2

Series3

Series4

HPK L1 teststructure

• exact resistance value is difficult to measure, currents are low

• value is irrelevant though, as long as R_inter >> R_poly

• R_inter on babydetector ~ 10 Gohm (?)

interstrip resistance baby detector

0.00E+00

2.00E-11

4.00E-11

6.00E-11

8.00E-11

1.00E-10

-1.4 -1.0 -0.6 -0.2 0.2 0.6 1.0 1.4

U (V)

I (A

)

interstrip 1

interstrip 2

interstrip 3

HPK L1 teststructures

• total strip capacitance includes both neighbors plus backplane capacitance

• capacitance reaches plateau at ~10V

• frequency dependence:

total strip capacitance

0

5

10

15

20

0 30 60 90 120

bias (V)

C_t

ot

(pF

)

1kHz

2kHz

5kHz

10kHz

20kHz

50kHz

100kHz

200kHz

500kHz

1MHz

Capacitance at 1 MHz: ~8.5pFCap/cm: ~1.1 pF/cm

Total strip capacitance (pF)

0

2

4

6

8

10

1 10 100 1000

frequency (kHz)

C_t

ot

(pF

)

Series1

Series2

HPK L1 teststructures

•interstrip capacitance to one neighbor: ~3 pF => 0.39 pF/cm to both neighbors: ~5.5 pF => 0.71 pF/cm

interstrip capacitance

01234567

1 10 100 1000

freq (kHz)

C (

pF

) Cint both

Cint both

Cint one neighbor

MOS structure

• MOS (metal-oxide- silicon) structure measure flatband voltage use only 0.1V oscillator

amplitude on LCR high frequency (200kHz) flatband shift to negative

values? interpretation not yet

clear MOS structure

0

1

2

3

4

5

-20 -15 -10 -5 0 5 10

gate (V)

C (

pF

)

Series1