Master Project Intermediate presentation – 03/07/14 Cindy Wiese

Goal of the project Microchannels: Vertical sidewalls Tilted tips Contains the liquid scintillator Aluminium coating for light reflection Photodiodes: p-i-n structure (in reverse voltage) to optimize electrons collection in the depletion zone Amorphous silicon to avoid radiation damages Silicon Reflective coating Photodiode Pyrex

Channels roughness Etching process Etching profil along the channel width Roughness at the middle of the channel 40% KOH etching, 60°C 40% KOH etching, 60°C + 3µm wet ox + BHF etching 40% KOH + IPA etching, 60°C

Notching effect Channels length = 5 mm Etching process Etching profil along the channel length D 40% KOH etching, 60°C 4.88 µm 40% KOH etching, 60°C + 3µm wet ox + BHF etching 6.13 µm 40% KOH + IPA etching, 60°C 1.26 µm

Conclusion on roughness improvement processes KOH etching + Wet ox + BHF etching: Improve microscopic roughness KOH + IPA etching: Improve macroscopic roughness (smoothed profil, low notching)

Notching effect 40% KOH etching Channel length Etching profil along the channel length D 5 mm 4.88 µm 8 mm µm 13 mm 11.9 µm 50 mm 14.6 µm

Wafers inventory Microfluidic tests: Wafer n°KOH etchingAl sputteringBonding 1 Channels perforated 2 Wafer broken 3 Wafer broken in SPTS after TM 4 Wafer damaged by TM 5 Waiting for Anodic Bonding

Wafers inventory Scintillation detectors: Wafer n° KOH etching Al sputtering BondingGrinding 1 HCl decontamination after bonding  Al etched 2 Pyrex broken Used for measurements