10/09/2002 P. Roy G. Pellegrini, A. Al-Ajili, L. Haddad, J. Melone, V. O'Shea, K.M. Smith, V. Wright, M. Rahman Patrick Roy Study of irradiated 3D detectors

10/09/2002 P. Roy Overview Introduction Fabrication: -Dry etching -Laser machining -Photoelectrochemical etching -Electrical contacts Results: -Before irradiation -After irradiation Conclusion

10/09/2002 P. Roy Introduction

10/09/2002 P. Roy Motivation V dep  qw 2 N eff /2  time [years] V d e p (  m ) [ V ] standard silicon oxygenated silicon operation voltage: 600 V 6000 e for B-layer 6000 e for B-layer Damage projection for the ATLAS B-layer (3 rd RD48 STATUS REPORT CERN LHCC , LEB Status Report/RD48, 31 December 1999). 3D detector!

10/09/2002 P. Roy Fabrication steps Creation of the holes Creation of the electrodes Connection to the electronics Wire bonding Bump bonding Dry etching Laser drilling PEC etching Shottky-Schottky n-Shottky p-n junction

10/09/2002 P. Roy Dry etching Diameter: 10  m Spacing: 85  m Depth: 130  m Etch time: 100 minutes Aspect ratio 13:1 Expect < 20:1 Inductively Coupled Plasma Mask: photoresist Gas: SF 6 Coating: C 4 F 8

10/09/2002 P. Roy Laser machining in Si Ti:Sapphire laser (TOPS facility at Strathclyde University*) 3 mJ pulse with duration of 40 fs at 1 kHz repetition rate 810 nm wavelength or 405 nm wavelength (doubling crystal) * In collaboration with D.A. Jaroszynski and D. Jones of Strathclyde University Diameter: Front:  m Back:  m Spacing: 85  m Depth: 200  m Power: 75 mW Time: 5 sec/holes Aspect ratio 25:1

10/09/2002 P. Roy PEC etching in Si Aspect ratio 12:1 Expect > 100:1 Diameter: 10  m Spacing: 25  m Depth: 120  m Etch time: 480 minutes Mask: 100 nm l/s SiN Solution: 2.5% aqueous HF

10/09/2002 P. Roy Electrical contacts Tracks of Al (150 nm) (over the SiO 2 layer) Metal evaporation: Ti (33 nm) Pd (33 nm) Au (150 nm) Wire bonding (25  m wire)

10/09/2002 P. Roy Results with  particles Resolution ~27% ~54% CCE ~60% ~47% Material Silicon GaAs

10/09/2002 P. Roy Results with X-Ray in GaAs Resolution ~44% CCE ~70%

10/09/2002 P. Roy Irradiation at PSI Irradiation with 300 MeV/c  at PSI (Villigen*) Bunch of 1 ns every 19 ns. Flux of  /cm 2 /day. Fluences between and  /cm 2. Irradiation performed by K. Gabathuler, M. Glaser and M. Moll.

10/09/2002 P. Roy Leakage current

10/09/2002 P. Roy Fabrication comparison Dry etching Laser drilling PEC etching Metal evaporation n or p type doping 13:1 25:1 12:1 <20:1 ~50:1 >100:1 Technique currentlyexpected Standard process Expensive Most promising Sidewall damages yes no Aspect ratios Simple process Complex process Good for GaAs Good for Si

10/09/2002 P. Roy Conclusion Dry etching ==> 13:1 in silicon Laser machining ==> 25:1 material independent PEC etching ==> 12:1 in silicon Irradiated working devices in Si and GaAs

10/09/2002 P. Roy In development Run II with fs laser in GaAs and SiC Improvement of PEC etching Improvement of dry etching Connection to DAC readout chip Better contacts Proton irradiation of samples