1

Simulations of irradiated MSSDs with p-stop

Parameter Value

n+ / p+ doping [cm-3] 5e18

Neff (320P) [cm-3] 3.4e12

Neff (200P) [cm-3] 3e12

Neff (120P) [cm-3] 1.5e12

implant thickness [µm] 1.5

backplane diffusion depth (320P) [µm]

33

backplane diffusion depth (200P) [µm]

115

backplane diffusion depth (FTH200P) [µm]

10

backplane diffusion depth (120P) [µm]

215

Np [cm-3] 3e16, 4e16, 5e16

p-stop thickness [µm] 0.5, 1.0, 1.5

SiO2 thickness [µm] 0.5

T [K] 253, 273, 293

area factor 30490

F (Cint) 1.0 MHz

F (Cback) 1.0 kHz

Qf (irr.) [cm-2] 1e12 [1]

Qf (unirr.) [cm-2] 1e10, 5e10, 4e11

5-strip structure for 7-80 and 5-120 regions

Two-level radiation damage model [1]

Level [eV]

σn [cm-2]

σp [cm-2]

Introduction rate [cm-1]

EC - 0.42 2e-15 2e-14 1.613EC - 0.46 5e-15 5e-14 0.9

1 MeV neutron equivalent doses for the simulations (from CMS irr. campaign)

Device thickness[μm]

Proton 1 MeV neqv fluence[cm-2]

1 MeV n fluence[cm-2]

1 MeV neqv summed fluence[cm-2]

≥ 200 3.0e14 4.0e14 7.0e14

≥ 200 1.0e15 5.0e14 1.5e15

≥ 200 1.5e15 6.0e14 2.1e15

≤ 200 3.0e15 7.0e14 3.7e15

< 200 1.3e16 1.0e15 1.4e16

p-stop configurations (preliminary)

p-stop count p-stop width[µm]

spacing[µm]

2 2 10

2 4 6

1 14 0

Total p-stop width = constant

[1] M. Petasecca et al. NIM A 563 (2006) 192-195.

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• By lowering the value of Qf from 5e10 cm-2 to 2.7e10 cm-2 the initial dip of measured curve is produced by simulation. At higher voltages simulated curve is within ~2 % of measurement.

• At higher value of non-irradiated inversion layer oxide charge Qf = 4e11 cm-2 simulation does not match the measurement and fails at ~600 V due to high E at p-stop edges.

• For the irradiation simulations, p-stop depth was varied by dp = 1.0 and 1.5 μm

• Irradiated inversion layer oxide charge Qf = 1e12 cm-2

region 5

region 7

TEST ID: 15010

TEST ID: 15016

• Simulation dp = 1.5 μm

• Qf = 5e10 cm-2

Interstrip capacitances of measured and simulated non-irradiated 200P detectors @ +20 °C

Initial dip not produced by simulation

• Simulation dp = 1.5 μm

• Qf = 5e10 cm-2

region 7

• Simulation dp = 1.5 μm

• Qf = 2.7e10 cm-2

TEST ID: 15016

3

• Are the strips are short-circuited for Np = 3e16 until Vd has removed electrons from the inversion layer?

• e- density between two strips and p-stops for

Φ = 7e14 cm-2 and wp = 2μm. Isolation fails for smaller Np @ low Vd?

• Widest wp has the lowest Cint and Vd where minimum Cint is reached for Np = 3e16

Cback

Cint

Qf = 1e12 cm-2

p-stop thickness = 1.0 μm

f = 1.0 kHz

f = 1.0 MHz

Irradiated 200P 7-80 region for varying Np and p-stop count/width @ -20 °C

• Radiation damage removes electrons from the inversion layer → isolation reached at lower Vd?

4

p-stop thickness = 1.0 μm

Cint Cback • At higher T electrons removed

from inversion layer more quickly → min. Cint reached at lower Vd 350 V (-20 °C) → 290 V (+20 °C)

• e- density between two strips and p-stops for

Φ = 7e14 cm-2 and wp = 2μm

Irradiated 200P 7-80 region for varying Np and p-stop count/width @ +20 °C

5

Irradiated 200P 7-80 region for varying Np and p-stop count/width @ -/+20 °C

p-stop thickness = 1.5 μm = implant thickness

Cint @ -20 °C

Ileak @ -20 °C

• e- density between two strips and p-stops for Φ = 7e14 cm-2 and wp = 2μm

Cint @ +20 °C

Ileak @ +20 °C

n @ -20 °C

n @ +20 °C

• No step in leakage current

observed for both Np

• No high values of Cint observed

after ~30 V

• Low e- density even at

low voltage for both Np

Superior configuration to dp = 1.0 μm