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14 pages, 5389 KiB

Open AccessArticle

Impact of the Guard Rings on Self-Induced Signal and Leakage Current in Trench-Isolated Low Gain Avalanche Diodes

by Gordana Lastovicka-Medin, Gregor Kramberger, Jiri Kroll and Mateusz Rebarz

Sensors 2025, 25(10), 3006; https://doi.org/10.3390/s25103006 - 10 May 2025

Viewed by 703

In this contribution, we explored the interplay of guard ring (GR) configuration and isolation structures, as well as irradiation effects, which all together create a rich landscape of phenomena such as self-induced signals (“ghosts”) in trench-isolated Low-Gain Avalanche Diodes (TI-LGADs). The ghost effect is related to the increased surface current due to presence of SiO₂ trenches (and defects) in studied diodes, but it is also affected by interplay between the guard ring(s) and the n⁺ bias ring, implanted in inter-pixel region of these devices. In double-trenched sensors, the n⁺ bias ring is inserted in between the two trenches. We present the investigation on the role of these structures on the self-induced signals in trench-isolated sensors from two different productions (RD50 and AIDAinnova). The sensors from the first production have multiple guard rings, whereas the second type of devices feature only one. Detailed examination of the ghost effect and leak current was performed when guard rings were left floating or connected to the pixels (brought to the same potential). The results show that guard ring configuration in trenched sensors can be critical for the leak current and the presence of a ghost signal. To our best knowledge, the latter problem has not been investigated yet. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications (2nd Edition))

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12 pages, 18216 KiB

Open AccessArticle

Optical Efficiency Enhancement of Nanojet-Based Dielectric Double-Material Color Splitters for Image Sensor Applications

by Oksana Shramkova, Valter Drazic, Bobin Varghese, Laurent Blondé and Valerie Allié

Nanomaterials 2021, 11(11), 3036; https://doi.org/10.3390/nano11113036 - 12 Nov 2021

Cited by 7 | Viewed by 2677

Abstract

We propose a new type of color splitter, which guides a selected bandwidth of incident light towards the proper photosensitive area of the image sensor by exploiting the nanojet (NJ) beam phenomenon. Such splitting can be performed as an alternative to filtering out part of the received light on each color subpixel. We propose to split the incoming light thanks to a new type of NJ-based near-field focusing double-material element with an insert. To suppress crosstalk, we use a Deep-Trench Isolation (DTI) structure. We demonstrate that the use of a dielectric insert block allows for reduction in the size of the color splitting element. By changing the position of the DTI, the functionality of separating blue, green and red light can be improved. Full article

(This article belongs to the Special Issue Advanced Nanomaterials for Quantum Technology, Sensor and Health Therapy Applications)

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5 pages, 1672 KiB

Open AccessProceeding Paper

Analysis of pn Junction Deep Trench Isolation with SU-8/SiO₂-Liner Passivation in a Linear Butt-Coupled 3D CMOS Si Photodetector Array

by Iman Sabri Alirezaei, Joerg Vierhaus and Edmund P. Burte

Proceedings 2017, 1(4), 557; https://doi.org/10.3390/proceedings1040557 - 7 Jun 2017

Cited by 1 | Viewed by 4677

Abstract

The realization of 30 µm-deep trench isolation in a linear array of butt-coupled 3D CMOS silicon photodetectors is investigated by implementing the formation of a shallow n⁺-p junction and SiO₂-liner over the trench sidewalls as well as the SU-8 filling trenches for passivation. The dependency of the dark I-V curve on the trench isolation scheme is analyzed by monitoring the dynamic dark I-V measurements of four samples including the schemes of single-trench isolation with different widths and the scheme of double-trench isolation. The highest and the lowest dark currents are measured in the detectors with the widest single-trench isolation and the double-trench isolation, respectively. Full article

(This article belongs to the Proceedings of Proceedings of Eurosensors 2017, Paris, France, 3–6 September 2017)

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