Calculations of 3D Weighting Field Profiles for 3D Detectors

1. 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

2. BNL 3D detector: 1 column design n+(column),0 p+, 0 p+ (implant),0 n+, the collecting electrode column, 1

3. n+ n+ cut plane @ 1um cut plane @ 2um n+ n+ cut plane @ 4um cut plane @ 10um Weighting field highest near the surface

4. n+ n+ cut plane @ 20um cut plane @ 30um n+ n+ cut plane @ 50um cut plane @ 70um Weighting field highest near the collecting n+ column, lowest under p+ electrodes, and is at ½ strength in the middle (non-zero)

5. n+ n+ cut plane @ 150um cut plane @ 250um n+ cut plane @ 268um cut plane @ 271um

6. Potential Cutline Cutline

7. cut plane @ 280um cut plane @ 290um Some weighting field still exists near the unprocessed back side (non-zero) cut plane @ 300um

8. BNL 3D detector: 2 columns design p+ n+(column) p+ (column) n+, the collecting electrode column, 1

9. n+ n+ cut plane @ 0um cut plane @ 150um n+ n+ cut plane @ 268um cut plane @ 250um Weighting field highest near the collecting n+ column, lowest between p+ columns And non-collecting n+ column, and is at about ½ strength in the middle (non-zero)

10. Cutline

11. cut plane @ 271um cut plane @ 275um cut plane @ 278um cut plane @ 281um

12. cut plane @ 285um cut plane @ 290um Some weighting field still exists near the unprocessed back side (non-zero) cut plane @ 300um

13. 3D detector: BNM/ITC - IRST p+ n+(column) p+ (column) n+, the collecting electrode column

14. cut plane @ 0um cut plane @ 7um cut plane @ 17um cut plane @ 12um Weighting field lowest near the surface of p+ columns

15. cut plane @ 18um cut plane @ 20um cut plane @ 24um cut plane @ 28um

16. n+ n+ cut plane @ 30um cut plane @ 50um n+ n+ cut plane @ 150um cut plane @ 250um Weighting field highest near the collecting n+ column, lowest between p+ columns And non-collecting n+ column, and is at about ½ strength in the middle (non-zero) (same)

17. Cutline

18. n+ n+ cut plane @ 269um cut plane @ 271um n+ n+ cut plane @ 280um cut plane @ 273um

19. n+ n+ cut plane @ 285um cut plane @ 290um Weighting field at the surface of n+ columns is similar to that of the STC 3D detector n+ cut plane @ 300um

20. 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