KIT – Universität des Landes Baden-Württemberg undnationales Großforschungszentrum in der Helmholtz-Gemeinschaft

Institut für Experimentele Kernphysik,

www.kit.edu

Simulation results on p-stop/p-spray depth/concCrosscheck of HPK workshop Jan 2013 talk of W. Trebersburger (HEPHY Vienna)

IEKP, KIT2 08.02.2013 Martin Strelzyk – Simulation results on pstop doping depth and concentation

Comparison of SRP measurements at HEPHY

~ summer 2011:

N-strip: 1e17 cm-3, d=1.4 umP-stop: ???P-spray: 1-2e14 cm-3, d=0.2 um

~ Jan. 2013:

N-strip: 1-2e19 cm-3, d=2.2 umP-stop: 4e15 cm-3, d=1.6 umP-spray: 1e15 cm-3, d=1.5 um

Fig.: SPR measurements of doping profiles for n-strips and p-stop isolation presented at HPK workshop at CERN in Jan. 2013(Wolfgang Trebersburg, HEPHY Vienna)

Check with help of simulation tool Synopsys T-CAD!

IEKP, KIT3 08.02.2013 Martin Strelzyk – Simulation results on pstop doping depth and concentation

Interstrip ResistanceElectrical conductance C in Synopsys T-CAD corresponds to admittance A per default.Definition of admittance C: C=1/Z with Z= R + iX, where R is the resistance and the imaginary part X is the reactance.Here we assume Z ~ R and hence R = 1/A

Peak like inClaudio‘s paper

Peak not yet understood

Sufficient strip isolation only above ~100V

P-stop conc

Q_Ox 1.0e11 cm^-2P-stop depth 1.0umP-stop width 6.0umN-strip depth 1.0umBulk doping 3.4e12 cm^-3

1e15 cm^-3

6e16 cm^-3

1e16 cm^-3

3e16 cm^-3

1e17 cm^-3

IEKP, KIT4 08.02.2013 Martin Strelzyk – Simulation results on pstop doping depth and concentation

R_int simulated with values from SPR measurements from HEPHY presented at HPK workshop in Jan. 2013

320P typeBulk doping =3.4e12 cm^-3P-stop conc = 4e15cm^-3P-stop depth = 1.6 umP-stop width = 6umN-strip depth = 2.2 umOxide charge varied from 1e11cm^-2 to 3e12cm^-2

Increase of oxide charge due to surface damage caused by radiation accumulates more electrons between adjecent strips

R_int decreases

Strip isolation strongly depends on surface damage!

increase of Q_Ox decrease of R_int

1e11cm^-2

3e11cm^-2

8e11cm^-2

3e12cm^-2

IEKP, KIT5 08.02.2013 Martin Strelzyk – Simulation results on pstop doping depth and concentation

• Variation of Q_Ox from 1e11cm-2 to 2e12cm-2

• 3 different doping concentrations of p-stop pattern

Q_O

x increases

P-stop conc4e15 cm-2

P-stop conc3e16 cm-2

P-stop conc1e16 cm-2

sufficient R_int

sufficient R_int

sufficient R_int

As expected, with higher p-stop conc.R_int is more sufficient at lower V_biasNext: how look the E-fields like?

IEKP, KIT6 08.02.2013 Martin Strelzyk – Simulation results on pstop doping depth and concentation

Now: strip n depth const. 1.0 um and variation of p-stop depth p_d = 1.0, 1.6 and 2.0 um

Strip and p-stop concentrations and doping depths taken from SPR measurements presented in Jan. 2013

Increasing of oxide charge leads to R_int values of some Ohm…(instead of GOhm)

Deeper p-stop implantation is better in that way, that R_int becomes sufficient at lower voltages with increasing Q_Ox

Check of E-field strenghts necessary!

Q_Ox = 1e11 cm-2

Q_Ox = 8e11 cm-2

Q_Ox = 4e11 cm-2

p_d = 1.0um

p_d = 2.0um

p_d = 1.6um

IEKP, KIT7 08.02.2013 Martin Strelzyk – Simulation results on pstop doping depth and concentation

Now: strip p depth const. 1.0 um and variation of n-strip depth n_d = 1.0, 1.5 and 2.0 um

Q_Ox = 1e11 cm-2 Q_Ox = 4e11 cm-2

Q_Ox = 8e11 cm-2

Strip and p-stop concentrations and doping depths taken from SPR measurements presented in Jan. 2013

Increasing of oxide charge leads to R_int values of some Ohm…(instead of GOhm)

It looks like p-stop depth of 1.0 um and a doping conc of 4e15 cm-3 would not guarantee good strip isolation

Check of E-field strenghts necessary!

IEKP, KIT8 08.02.2013 Martin Strelzyk – Simulation results on pstop doping depth and concentation

Summary

R_int simulations give a first feeling of how the strip isolation depends on doping concentrations and doping depths of implants.C_int is not influenced significantly considering doping depths (not shown here).Check of „new“ implant parameters presented at hpk workshop was done.

Still no meaningful suggestions for implant parameters possible, because important sensor characteristics like e-field strength and CCE have to be studied.