1. Modeling and simulation of charge collection properties for 3D-Trench electrode detector Hao Ding a, Jianwei Chen a, Zheng Li a,b,c, *, Shaoan Yan a a Xiangtan University, China b Center for Semiconductor Particle and photon Imaging Detector Development and Fabrication, Xiangtan, China c Brookhaven National Laboratory, Upton, NY, USA (Before 2/7/2014) 2014.10

2. Structure of 3D-Trench electrode detector (Hexangular) Zheng Li, Nucl. Instr. and Meth A658(2011) 90-97.

3. Structure of 3D-Trench electrode detector A single cell of the 3D-trench electrode detector(hexangular type) Some common geometry Zheng Li, Nucl. Instr. and Meth A658(2011) 90-97.

4. Electric field of cylindrical unit cell p + column n + trench n + column p + trench The junction is at the outer ring trench (3D-Trench-ORJ) The junction is at the center electrode column (3D-Trench-CJ) Analytical calculations show that, the electric filed profile of 3D- Trench-ORJ Si detector can be nearly uniform and it has much smaller maximum electric field than that in 3D-Trench-CJ Si detectors. All the simulated 3D-trench detectors are the type of 3D-Trench-ORJ. Cylindrical detector Zheng Li, Nucl. Instr. and Meth A658(2011) 90-97. P-type bulk P-bulk Radiation hardness

5. Electric field of cylindrical unit cell E-field profile of cross section from full 3D device simulation, V=100 V, φ=1x10 16 n eq /cm 2. N eff = 1x10 14 cm -3, V=100 V, V fd =59 V, r 0 =5 um, R=40 um. [1] Theoretical value Simulation result [1] Zheng Li, Nucl. Instr. and Meth A658(2011) 90-97.

6. Induced current and charge collection Schematic view of a MIP incident in a 3D-trench detector. r0r0 R MIP

7. Induced current and charge collection The induced current : Collected charge:

8. Full 3D device simulation of 3D-trench detectors The electric field and weighting field profiles are obtained from full 3D device simulation(with silvaco TCAD).

9. 3D-trench detectors with square shape n + 1x10 19 /cm 3 p + 1x10 19 /cm 3 p-type bulk The initial doping concentration of p-type bulk is 1x10 12 cm -3. The effective doping concentration N eff of Si bulk changes with radiation fluence:. is 0.01 for protons. Doping concentration Cross section

10. Full 3D device simulation of 3D-trench detectors Electric field profiles of non-irradiated 3D-trench detectors (at cross section). E-field profile at V=2 V

11. Full 3D device simulation of 3D-trench detectors Electric field profiles of 3D-trench detectors (at cross section) at radiation fluence of 1x10 16 n eq /cm 2. E-field profile at V=20 V E-field profile at V=40 V

12. Full 3D device simulation of 3D-trench detectors E-field profile at V=80 V E-field profile at V=100 V Electric field profiles of 3D-trench detectors (at cross section) at radiation fluence of 1x10 16 n eq /cm 2.

13. Simulation of the weighting field SiO 2 electrode (Vacuum or Insulator) 1 V 0 V

14. Simulation of the weighting field Potential profile at V=1 VWeighting field profile Simulation results (at cross section)

15. Charge collection simulation Induced current at various MIP incident position(r I is from r 0 to R):

16. Charge collection simulation For the non-irradiated 3D-trench detector:

17. Charge collection simulation For the irradiated 3D-trench detector: Charge collection at the fluence of 1x10 15 n eq /cm 2 Charge collection at the fluence of 3x10 15 n eq /cm 2

18. Charge collection simulation For the irradiated 3D-trench detector: Charge collection at the fluence of 7x10 15 n eq /cm 2 Charge collection at the fluence of 1x10 16 n eq /cm 2

19. Charge collection simulation Total collected charge reduce with the increasing radiation fluence:

20. Charge collection simulation The average total collected charge generated by a MIP at a random incident position of a 3D-trench electrode detector with square geometry: The number of incident MIPs per unit area is n 1. The linear density of total collected charge for MIPs incident at diagonal of detector surface is Q(r).

21. 21 Charge collection simulation The average total collected charge of a cylindrical 3D-trench electrode detector with different electrode spacing: Electrode spacing

22. Summary of simulation 1.For a non-irradiated detector, the total collected charge is independent of the particle incident position. 2. For an irradiated detector, the total collected charge changes with various incident position. This is due to the fact that the probability of hole trapping and electron trapping will change with the particle incident position, which affects the composition of electron and hole contributions to the induced current and therefore the total collected charge. 3. Shortening electrode spacing can greatly increase the collected charge

23. Charge collection simulation Thank you