Abstract
Low-Gain Avalanche Diodes are a recently-developed class of silicon sensors. Characterized by an internal moderate gain that enhances the signal amplitude and if built on thin silicon substrates of a few tens of microns, they feature fast signals and exhibit excellent timing performance. Thanks to their fast timing they are planned to be exploited in timing detectors in High-Energy Physics experiments, for example for the upgrades of the ATLAS and CMS detectors at the High Luminosity Large Hadron Collider (HL-LHC) at CERN. However, to achieve a spatially uniform multiplication a large pixel pitch is needed, preventing a fine spatial resolution. To overcome this limitation, the AC-coupled LGAD approach was introduced. In this type of device, metal electrodes are placed over an insulator at a fine pitch, and signals are capacitively induced on these electrodes. The fabrication technology is similar for the two LGAD families, although a fine tuning of a few process parameters needs to be carefully studied. Other R&D efforts towards detectors that can simultaneously provide good time and spatial resolution, based on the LGAD concept, are under way. These efforts aim also to mitigate the loss of performance at high irradiation fluences due to the acceptor removal within the gain layer. In this paper we describe the main points in the fabrication of LGADs and AC-LGADs in a clean-room. We also discuss novel efforts carried on related topics.
Highlights
Detection of minimum ionizing particles is achieved with silicon-based detectors
Leveraged by the interest of the High Energy Physics (HEP) community in its fast timing performance, Low-Gain Avalanche Diode concept (LGAD) have reached an advanced stage of maturity
The physics reach of two mayor experiments in HEP (ATLAS and CMS) critically depends on the performance of meter-squared detectors based on this technology
Summary
Detection of minimum ionizing particles (mips) is achieved with silicon-based detectors. It is worth mentioning that there are families of LGADs which are fabricated on thick substrates: iLGADs [13] are double-sided LGADs (multiplication layer on one side and hole-collecting finepitch electrodes on the opposite side of the wafer) which are fabricated on thick high-resistivity silicon wafers As such, they loose the timing performance but, being the signals internally amplified, are still useful when soft X-ray detection is needed. Avalanche PhotoDiodes (APD) are well-known and extensively used silicon devices with an internal amplification in the range 10–200, adjustable by applying a suitable external bias voltage [15] They are used for scintillation light detection in High energy Physics experiments [16, 17]. We report some of the efforts carried on to overcome such limitations
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
