VCI2019 - The 15th Vienna Conference on Instrumentation

Processing of AC-coupled n-in-p pixel detectors on MCz silicon using atomic layer deposition (ALD) grown aluminium oxide

Not scheduled

15m

Vienna University of Technology

Board: 87

Poster Semiconductor Detectors Poster Session B

Speaker

Jennifer Ott (Helsinki Institute of Physics (FI))

Description

We report on the fabrication of capacitively-coupled (AC) n+-in-p pixel detectors on magnetic Czochralski silicon substrates. In our devices, we employ a layer of aluminium oxide (Al${}_2$O${}_3$) grown by atomic layer deposition (ALD) as dielectric and field insulator, instead of the commonly used SiO${}_2$. As shown in earlier research, Al${}_2$O${}_3$ thin films exhibit high negative oxide charge, and can thus serve as a substitute for p-stop/p-spray insulation implants between pixels. In addition, they provide far higher capacitance densities than SiO${}_2$ due to their high dielectric constant, permitting more efficient capacitive coupling of pixels. Furthermore, metallic titanium nitride (TiN) bias resistors are presented as an alternative to punch-through or poly-Si resistors.

Devices obtained by the abovementioned process are characterized by CV, IV, and TCT measurements, and by 2 MeV proton microprobe. Results show the expected high negative charge of the Al${}_2$O${}_3$ dielectric, uniform charge collection efficiency over large areas of pixels, and acceptable leakage current densities.

Presentation materials

VCI_2019_JO_final.pdf