Hybrid-Contact Planar HPGe Process Vehicle Toward Ring-Contact Designs

Fuente: arXiv
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Main Authors: Dong, Kunming, Mei, Dongming, Panamaldeniya, Shasika, Karki, Anupama, Burns, Patrick, Bhataarai, Sanjay
Format: Preprint
Published: 2026
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author Dong, Kunming
Mei, Dongming
Panamaldeniya, Shasika
Karki, Anupama
Burns, Patrick
Bhataarai, Sanjay
author_facet Dong, Kunming
Mei, Dongming
Panamaldeniya, Shasika
Karki, Anupama
Burns, Patrick
Bhataarai, Sanjay
contents Rare-event searches including dark matter, coherent elastic neutrino--nucleus scattering (CE$ν$NS), and neutrinoless double-beta decay (0$νββ$) require high-purity germanium (HPGe) detectors with ultralow noise, stable backgrounds, and electrode geometries that can scale to larger single-crystal masses. Ring-contact (ring-and-groove) designs address scalability by shaping the electric field to preserve low-capacitance readout, but their nonplanar topology motivates a lithium-contact process that is compatible with conformal deposition and robust high-voltage operation. As a process demonstration toward future ring-contact prototypes, we fabricate and characterize a hybrid-contact planar HPGe device, KL01. Here, ``hybrid'' denotes an $n^{+}$ contact formed by an in-house lithium-suspension paint followed by controlled thermal diffusion, combined with an AJA-developed a-Ge/Al $p^{+}$ contact and a-Ge sidewall passivation. At 77~K the device exhibits pA-scale leakage current under kV bias, a depletion plateau near $V_{\mathrm{dep}}\approx 1300$~V, and energy resolutions of 1.57~keV FWHM at 59.5~keV and 2.57~keV FWHM at 662~keV. These results validate the compatibility of the paint-and-diffuse lithium process with thin-film a-Ge/Al contacts and establish a practical fabrication workflow to be extended to ring-and-groove electrodes for next-generation rare-event HPGe modules.
format Preprint
id arxiv_https___arxiv_org_abs_2601_08934
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Hybrid-Contact Planar HPGe Process Vehicle Toward Ring-Contact Designs
Dong, Kunming
Mei, Dongming
Panamaldeniya, Shasika
Karki, Anupama
Burns, Patrick
Bhataarai, Sanjay
Instrumentation and Detectors
High Energy Physics - Experiment
Nuclear Experiment
Rare-event searches including dark matter, coherent elastic neutrino--nucleus scattering (CE$ν$NS), and neutrinoless double-beta decay (0$νββ$) require high-purity germanium (HPGe) detectors with ultralow noise, stable backgrounds, and electrode geometries that can scale to larger single-crystal masses. Ring-contact (ring-and-groove) designs address scalability by shaping the electric field to preserve low-capacitance readout, but their nonplanar topology motivates a lithium-contact process that is compatible with conformal deposition and robust high-voltage operation. As a process demonstration toward future ring-contact prototypes, we fabricate and characterize a hybrid-contact planar HPGe device, KL01. Here, ``hybrid'' denotes an $n^{+}$ contact formed by an in-house lithium-suspension paint followed by controlled thermal diffusion, combined with an AJA-developed a-Ge/Al $p^{+}$ contact and a-Ge sidewall passivation. At 77~K the device exhibits pA-scale leakage current under kV bias, a depletion plateau near $V_{\mathrm{dep}}\approx 1300$~V, and energy resolutions of 1.57~keV FWHM at 59.5~keV and 2.57~keV FWHM at 662~keV. These results validate the compatibility of the paint-and-diffuse lithium process with thin-film a-Ge/Al contacts and establish a practical fabrication workflow to be extended to ring-and-groove electrodes for next-generation rare-event HPGe modules.
title Hybrid-Contact Planar HPGe Process Vehicle Toward Ring-Contact Designs
topic Instrumentation and Detectors
High Energy Physics - Experiment
Nuclear Experiment
url https://arxiv.org/abs/2601.08934