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Conception et modélisation des pixels de photodétection. Photodiodes PIN en silicium amorphe et polymorphe en vue de leurs utilisations comme détecteurs de particules.

Abstract : Since its creation the PICM laboratory has sought to develop new applications for hydrogenated amorphous silicon, a-Si: H. The research done has revealed that the a-Si:H is a material ideally suited for the detection of particles, while being resistant to radiation. It also has a low manufacturing cost, is compatible with existing technology and can be deposited over large areas. Thus, despite the low local mobility of charges (30 cm2 V-1 s -1 ), a-Si:H is a material of particular interest for manufacturing high-energy particle detection pixels. As a consequence of this, a collaboration with the LLR2 was formed during this PhD thesis in order to design and implement an experimental pixel stacked structure based on a- Si:H as a basic sensor element for an electromagnetic calorimeter. The structure of such a pixel consists of different components. First, a silicon PIN diode in a-Si:H is fabricated, followed by a bias resistor and a decoupling capacitor. Before such a structure is made and in order to optimize its design, it is essential to have an efficient behavioural model of the various components. Thus, our primary goal was to develop a two-dimensional physical model of the PIN diode using the SILVACO finite element calculation software. This a-Si:H PIN diode two-dimensional physical model allowed us to study the problem of crosstalk between pixels in a matrix structure of detectors. In particular, we concentrated on the leakage current and the current generated in the volume between neighbouring pixels. The successful implementation of this model in SPICE ensures its usefulness in other professional simulators and especially its integration into a complete electronic structure (PIN diode, bias resistor, decoupling capacity and low noise amplifier). Thanks to these modelling tools, we were able to simulate PIN diode structures in a- Si:H with different thicknesses and different dimensions. These simulations have allowed us to predict that the thicker structures are relevant to the design of the pixel detectors for high- energy physics. Applications in astronomy, medical imaging and the analysis of the failure of silicon integrated circuits, can also be envisioned. From a technological point of view, we focused on controlling the entire production chain (the choice of the electrode's material, the deposition sequence, the design of the masks and the clean room lithography). Thus, for example, we propose that the optimum material for the resistors and capacitors electrodes is Titanium, but due to its work function it is not recommended for manufacturing PIN diodes.
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Submitted on : Wednesday, July 21, 2010 - 2:38:53 PM
Last modification on : Wednesday, March 27, 2019 - 4:20:03 PM
Long-term archiving on: : Friday, October 22, 2010 - 3:18:03 PM


  • HAL Id : pastel-00004376, version 1



Razvan Negru. Conception et modélisation des pixels de photodétection. Photodiodes PIN en silicium amorphe et polymorphe en vue de leurs utilisations comme détecteurs de particules.. Physique Numérique [physics.comp-ph]. Ecole Polytechnique X, 2008. Français. ⟨pastel-00004376⟩



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