Calculations of 3D Weighting Field Profiles for 3D Detectors

Zheng Li

G. Carini, M. Li

3rd Workshop on Advanced Silicon Radiation Detectors (3D and P-type Technologies, Barcelona, Spain, April 14-16, 2004

BNL 3D detector: 1 column design

n+ , the collecting electrode column, 1

p+ (implant),0

p+ , 0

Weighting Field (1/cm)

n+ (column),0

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n+ n+

n+ n+

Weighting Field (1/cm) Weighting Field (1/cm)

Weighting Field (1/cm) Weighting Field (1/cm)

Weighting field highest near the surface

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n+ n+

n+ n+

Weighting Field (1/cm) Weighting Field (1/cm)

Weighting Field (1/cm) Weighting Field (1/cm)

Weighting field highest near the collecting n+ column, lowest under p+ electrodes,and is at ½ strength in the middle (non-zero)

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n+ n+

n+

Weighting Field (1/cm) Weighting Field (1/cm)

Weighting Field (1/cm) Weighting Field (1/cm)

Cutline

CutlineWeighting Field (1/cm)

Potential

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Weighting Field (1/cm) Weighting Field (1/cm)

Weighting Field (1/cm) Some weighting field still exists near the unprocessed back side (non-zero)

BNL 3D detector: 2 columns design

n+ , the collecting electrode column, 1

n+ (column)

p+ (column)

p+

Weighing field (1/cm)

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n+ n+

n+ n+

Weighting Field (1/cm) Weighting Field (1/cm)

Weighting Field (1/cm) Weighting Field (1/cm)

Weighting field highest near the collecting n+ column, lowest between p+ columnsAnd non-collecting n+ column, and is at about ½ strength in the middle (non-zero)

Cutline Weighting Field (1/cm)

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Weighting Field (1/cm) Weighting Field (1/cm)

Weighting Field (1/cm) Weighting Field (1/cm)

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cut plane @ 300um

Weighting Field (1/cm) Weighting Field (1/cm)

Weighting Field (1/cm) Some weighting field still exists near the unprocessed back side (non-zero)

3D detector: BNM/ITC - IRST

n+ , the collecting electrode column

n+ (column)

p+ (column)

p+

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cut plane @ 12um

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Weighting Field (1/cm) Weighting Field (1/cm)

Weighting Field (1/cm)Weighting Field (1/cm)

Weighting field lowest near the surface of p+ columns

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Weighting Field (1/cm) Weighting Field (1/cm)

Weighting Field (1/cm) Weighting Field (1/cm)

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cut plane @ 150um cut plane @ 250um

n+ n+

n+ n+

Weighting Field (1/cm) Weighting Field (1/cm)

Weighting Field (1/cm) Weighting Field (1/cm)

Weighting field highest near the collecting n+ column, lowest between p+ columnsAnd non-collecting n+ column, and is at about ½ strength in the middle (non-zero) (same)

Cutline

cut plane @ 269um cut plane @ 271um

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n+ n+

n+ n+

Weighting Field (1/cm) Weighting Field (1/cm)

Weighting Field (1/cm) Weighting Field (1/cm)

cut plane @ 285um

cut plane @ 300um

cut plane @ 290um

n+ n+

n+

Weighting Field (1/cm) Weighting Field (1/cm)

Weighting Field (1/cm) Weighting field at the surface of n+ columns is similar to that of the STC 3D detector

Summary Weighting field in 3D detectors is highly non-uniform

But it is distributed all throughout the detector (for pitch 50 µm) In the middle of the cell (between 4 columns), the weighting field is about half of the maximum

So the main limiting factor for CEE in 3D detectors may be electric fields