In this report we cover two special applications of Atomic Layer Deposition (ALD) thin films to solve these challenges of the very small size pixel detectors. First, we propose to passivate the p-type pixel detector with ALD grown Al2O3 field insulator with a negative oxide charge instead of using the commonly adopted p-stop or p-spray technologies with SiO2, and second, to use plasma-enhanced ALD grown titanium nitride (TiN) bias resistors instead of the punch through biasing structures. Surface passivation properties of Al2O3 field insulator was studied by Photoconductive Decay (PCD) method and our results indicate that after appropriate annealing Al2O3 provides equally low effective surface recombination velocity as thermally oxidized Si/SiO2 interface. Furthermore, with properly designed annealing steps, the TiN thin film resistors can be tuned to have up to several MO resistances with a few µm of physical size required in ultra-fine pitch pixel detectors.
|Journal||Nuclear Instruments and Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors and Associated Equipment|
|Publication status||Published - 2016|
|MoE publication type||A1 Journal article-refereed|
- bias resistor
Härkönen, J., Ott, J., Mäkelä, M., Arsenovich, T., Gädda, A., Peltola, T., Tuovinen, E., Luukka, P., Tuominen, E., Junkes, A., Niinistö, J., & Ritala, M. (2016). Atomic Layer Deposition (ALD) grown thin films for ultra-fine pitch pixel detectors. Nuclear Instruments and Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 831, 2-6. https://doi.org/10.1016/j.nima.2016.03.037