Results from a 2nd production run of low temperature wafer-wafer bonded pad-diodes for particle detection

Fuente: arXiv
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Autori principali: Wüthrich, J., Deplazes, K., Rubbia, A.
Natura: Preprint
Pubblicazione: 2025
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author Wüthrich, J.
Deplazes, K.
Rubbia, A.
author_facet Wüthrich, J.
Deplazes, K.
Rubbia, A.
contents We are investigating the use of low temperature wafer-wafer bonding in the fabrication of next-generation particle pixel detectors. This bonding technique could enable the integration of fully processed CMOS readout wafers with high-Z absorber materials, facilitating the creation of highly efficient X-ray imaging detectors. It might also facilitate the integration of structures embedded inside the wafer bulk, such as deep uniform gain layers. The bonding process results in a thin (nm-scale) amorphous layer at the bonding interface. To study the impact of this interface on detector operation, we fabricated simple wafer-wafer bonded pad diodes using high resistivity float-zone silicon wafers. Results from a first fabrication run of such diodes revealed that the presence of the bonding interface alters the depletion behaviour, with the interface acting as a heavily doped N++ layer. However, metal contamination of the bonding surfaces during fabrication compromised these results, making them unrepresentative of an ideal bonding interface. In this paper we present the results from a subsequent fabrication run, which does not exhibit this sort of metal contamination. These results confirm that the bonding interface behaves as a heavily doped N++ layer, even without contamination. Further, we discuss the reverse leakage current of the bonded samples, where current vs. voltage measurements show a behaviour which is consistent with current generated within the depletion region of the samples.
format Preprint
id arxiv_https___arxiv_org_abs_2505_07010
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Results from a 2nd production run of low temperature wafer-wafer bonded pad-diodes for particle detection
Wüthrich, J.
Deplazes, K.
Rubbia, A.
Instrumentation and Detectors
We are investigating the use of low temperature wafer-wafer bonding in the fabrication of next-generation particle pixel detectors. This bonding technique could enable the integration of fully processed CMOS readout wafers with high-Z absorber materials, facilitating the creation of highly efficient X-ray imaging detectors. It might also facilitate the integration of structures embedded inside the wafer bulk, such as deep uniform gain layers. The bonding process results in a thin (nm-scale) amorphous layer at the bonding interface. To study the impact of this interface on detector operation, we fabricated simple wafer-wafer bonded pad diodes using high resistivity float-zone silicon wafers. Results from a first fabrication run of such diodes revealed that the presence of the bonding interface alters the depletion behaviour, with the interface acting as a heavily doped N++ layer. However, metal contamination of the bonding surfaces during fabrication compromised these results, making them unrepresentative of an ideal bonding interface. In this paper we present the results from a subsequent fabrication run, which does not exhibit this sort of metal contamination. These results confirm that the bonding interface behaves as a heavily doped N++ layer, even without contamination. Further, we discuss the reverse leakage current of the bonded samples, where current vs. voltage measurements show a behaviour which is consistent with current generated within the depletion region of the samples.
title Results from a 2nd production run of low temperature wafer-wafer bonded pad-diodes for particle detection
topic Instrumentation and Detectors
url https://arxiv.org/abs/2505.07010