Electrical tests of ATLAS12A mini sensors UCSC status

1. Inter-strip resistance measurement of ATLAS12A samples :BZ3F Vs BZ3C and I-V measurements of ATLAS12A main sensor VitaliyFadeyev, Patrick Freeman,Zachary Galloway,Zhijun Liang, Hartmut F.-W. Sadrozinski, Kevin To SCIPP, UCSC

2. Electrical tests of ATLAS12A mini sensorsUCSC status • ATLAS12A main sensor • S10938_2244_VPX14757 • Inner cut sample wafer number: W751 W754 W756 W757 W758 W759 W764 W767 W768 W769 • Outer cut sample wafer number: W771 W772 W773 W774 W775 W777 W778 W782 W784 W785 • ATLAS12A Mini Samples • ATLAS12A samples irradiated with protons at Birmingham by 27MeV protons • 8 fluences : 1e12, 5e12,1e13,1e14,1e15,2e15,5e15 Neq/cm2 • Zones : BZ3C and BZ3F • This talk focus on the following measurements • IV curvefor ATLAS12A mainsensor • Inter-strip resistance for ATLAS12A mini sensors

3. I-V curve for ATLAS12A main sensors • Most of the main sensors are good • No breakdown up to 1000V • Leakage current less than 1uA Inner cut Outer cut

4. I-V curve of ATLAS12A main sensors: Inner cut sensors • W769 have a early breakdown before 500V • W764,W767 have a soft breakdown around 800V

5. I-V curve of ATLAS12A main sensors: Outer cut sensors • W773 has soft breakdown around 800V

6. UCSC measurements VS Hammamatsu inspection sheet: Inner cut sensor (1) • This measurements are consistent with Hammamatsu inspection sheet for most of the main sensors • W764 has low breakdown voltage in this measurement • W768 breakdowns above 920V in inspection sheet

7. UCSC measurements VS Hammamatsu inspection sheet: Inner cut sensor (2) • W767 and w769 have a soft breakdown at 800V in this measurement • Not visible in Hamamatsu inspection sheet

8. UCSC measurements VS Hammamatsu inspection sheet: Outer cut sensor • Soft breakdown in W773 in both Hamamatsu inspection sheet and this measurement

9. Summary of I-V study for ATLAS12A main sensor • I-V measurement of ATLAS12A • This measurement is consistent with Hamamatsu inspection sheet for Most of the main sensors • No breakdown up to 1000V • Leakage current less than 1uA • Discrepancies listed below

10. Update in Inter-strip resistance measurement of ATLAS12A samples :BZ3F Vs BZ3C

11. Reminder of the previous talk • There is some discrepancy of R_INT in proton radiated sample in different zones ( BZ3C , BZ3F) • Order of magnitude difference between BZ3C and BZ3F • BZ3F has a better inter-strip isolation • This difference between BZ3C and BZ3F is not expected • PTP structure should not affect R_INT Temp = -19 °C F=1e15 Neq/cm2 Temp = -19 °C F=1e14 Neq/cm2

12. Reminder of the previous talk • Discrepancy between BZ3C and BZ3F • Only exists in proton irradiated samples with F=1e14 Neq/cm2 and F=1e15 Neq/cm2 • Not seen in gamma radiated sensors • Not seen in other proton irradiated sensors with low fluences • Action item from last meeting • Check I-V curve of proton irradiated sensors with F=1e14 Neq/cm2 • Make sure the fluences of the sensors are labelled correctly • Check the impact of annealing • check the potential annealing issue in proton irradiated sensors

13. Check I-V curve of proton irradiated sensor • Measured in -10°C

14. Impact of annealing • One possible issue is that the BZ3F (1e14) sensor maybe have been annealed during proton radiation. • Try to annealed BZ3C (1e14) sensor to see the impact of annealing. • Annealed BZ3C (1e14) sensors in 80°C for two hours • Larger impact is founded due to annealing • The inter-strip resistance between BZ3C and BZ3F became small after annealing BZ3C

15. Summary of R_INT study • Found the impact of annealing is quite large in some sensors. • Need Birmingham new radiated samples to confirm the discrepancy.