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

Electrical tests of ATLAS12A mini sensors UCSC status ATLAS12A main sensor ◦ S10938_2244_VPX14757 ◦ Inner cut sample wafer number: W751W754W756W757 W758W759W764W767W768W769 ◦ Outer cut sample wafer number: W771 W772W773W774 W775W777W778W782W784W785 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 curve for ATLAS12A main sensor ◦ Inter-strip resistance for ATLAS12A mini sensors 2

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 3

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 4

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

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 6

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 7

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

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 This measurementHamamatsu inspection sheet W764Hard breakdown at 500VNo breakdown W768No breakdownHard breakdown at 920V W767Soft breakdown around 800VNo breakdown W769Soft breakdown around 800VNo breakdown W773Soft breakdown around 800V 9

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

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 11 Temp = -19 °C F=1e15 Neq/cm2 Temp = -19 °C F=1e14 Neq/cm2

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 12

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

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 14

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. 15