on the facilities for (AC-)LGAD design and fabrication

Gabriele Giacomini– September 3rd, 2020

US-Japan meeting

4” waferFrom Topsil

LGADDC-coupled1mmx1mm2mmx2mm3mmx3mmand arrays

AC-LGAD

Some AC-LGAD designs200 um pitch

500 um pitch

1mm pitch

100, 200 um pitch

100- um pitch

Layout Editor by L-Edit, photomasks fabrication by Photronics in Connecticut

TCAD numerical simulations

Mip @ different X

Current pulses for different X

Qualitatively assessment of LGAD/ACLGAD properties

Class 100 Cleanroom (lab 5) ~ 500 sq ftDedicated to silicon (no transition metals)

corri

dor

Class 100 Clean room

Oxidation, Annealing Furnaces

Class 100 Cleanroom

Wet Hoodfor wet-etch

(RCA I II, HF, HNO3, …)

Class 100 Cleanroom

Inspection station

Class 100 Cleanroom

Sputtering (AL, 1%Si/Al, Ti,

SiO2)

Class 100 Cleanroom

Double sided mask

aligner

Class 100 Cleanroom

Spray developer

Other Facilities• PECVD Oxide

& Si3N4, using class1000 clean room in another lab @ BNL

• DI water tank in the basement

• dehumidifier, Pressure Air System on the roof

• External service for ion-implantation

CMP

Laser dicing

Dry etching

Laser Dicing

• Laser Dicing Machine can cut single silicon detector out from the wafer, it can cut any shapes and holes (although not needed for LGAD)

Finish Processed Wafer

Laser Dicing MachineSingle Diced Detector

Packaging & assemblyDiced detector is wire-bonded to the read-out electronics on the PCB

Single Diced Detector

Packaged PIN-Maia Detector

Bench Tests• Electrical tests at the probe-station

select good detectors to be mounted• I-V C-V up to 200V with Keithley

4200SCS

Or…

• We use HP4145B connected to Keithley 2410 to do I-HV And HP4284A connected to Keithley 2410 to do C-HV up to 1000V

Irradiation facilities• TRIGA reactor in Ljubljana (Slovenia) for neutrons• Los Alamos National Lab for protons

Wish list:• BNL Tandem Van De Graaff generator

Low-activity lab radioactive source for dynamic tests (90Sr, X-rays, alphas, etc)