SiGeSn Quantum Dots in HfO2 for Floating Gate Memory Capacitors

Palade, Catalin; Slav, A.; Cojocaru, Ovidiu; Teodorescu, V. S.; Stoïca, T.; Ciurea, Magdalena Lidia; Lepadatu, Ana-Maria

doi:10.3390/coatings12030348

Cited by 9 publications

(3 citation statements)

References 33 publications

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“…As can be imagined, the SiGeSn crystallization process is hindered if it is embedded in an amorphous oxide matrix, this process requiring the diffusion-segregation for NCs nucleation. Previous studies on a tri-layer memory structure based on a thin floating gate layer of SiGeSn embedded in HfO 2 31 have revealed that the annealing temperature required for the formation of SiGeSn NC is in the range of 500–550 °C. This is also valid for thick amorphous layers of SiGeSnHfO 2 studied in this paper as resulted from HRTEM analysis presented above and the X-ray diffractograms in Fig.…”

Section: Resultsmentioning

confidence: 99%

Enhancing SiGeSn nanocrystals SWIR photosensing by high passivation in nanocrystalline HfO2 matrix

Dascalescu,

Palade,

Slav

et al. 2024

Sci Rep

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SiGeSn nanocrystals (NCs) in oxides are of considerable interest for photo-effect applications due to the fine-tuning of the optical bandgap by quantum confinement in NCs. We present a detailed study regarding the silicon germanium tin (SiGeSn) NCs embedded in a nanocrystalline hafnium oxide (HfO2) matrix fabricated by using magnetron co-sputtering deposition at room temperature and rapid thermal annealing (RTA). The NCs were formed at temperatures in the range of 500–800 °C. RTA was performed to obtain SiGeSn NCs with surfaces passivated by the embedding HfO2 matrix. The formation of NCs and β-Sn segregation were discussed in relation to the deposition and processing conditions by employing HRTEM, XRD and Raman spectroscopy studies. The spectral photosensitivity exhibited up to 2000 nm in short-wavelength infrared (SWIR) depending on the Sn composition was obtained. Comparing to similar results on GeSn NCs in SiO2 matrix, the addition of Si offers a better thermal stability of SiGeSn NCs, while the use of HfO2 matrix results in better passivation of NCs increasing the SWIR photosensitivity at room temperature. These results suggest that SiGeSn NCs embedded in an HfO2 matrix are a promising material for SWIR optoelectronic devices.

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Section: Resultsmentioning

confidence: 99%

Enhancing SiGeSn nanocrystals SWIR photosensing by high passivation in nanocrystalline HfO2 matrix

Dascalescu,

Palade,

Slav

et al. 2024

Sci Rep

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“…Targeting further improvement of memory properties, besides GeSi NCs in HfO2 multilayered floating gate approach [102], other approach [105] is to use Ge NCs alloyed with both Sn and Si. So, using storage nodes of SiGeSn is advantageous due to the low thermal budget for NCs formation by Sn presence, thus improving the suitability of NVM fabrication in terms of CMOS compatibility, at the same time with ensuring high stability by alloying with little Si.…”

Section: Charge Storage Propertiesmentioning

confidence: 99%

FROM Si NANOWIRES TO Ge NANOCRYSTALS FOR VIS-NIR-SWIR SENSORS AND NON-VOLATILE MEMORIES: A REVIEW

Lepadatu¹,

Stavarache²,

Palade³

et al. 2022

AnnalsARSciPhysChem

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"Nanocrystalline Si and Ge are ofhigh interestfor integrated Si photonics related to light emission, opticul sensors, photodetectors, solar energy harvesting and conversion devices, and also forfloating gate non-volatile memories (NVMs). In this review, we have focused on nanocrystalline porous Si (nc-PS) with extension to Si nanodots, and Ge nanocrystals (NCs)Zquantum dots (QDs)/nanoparticles (NPs) embedded in oxides (SiCh, TiCE, HfCh, AI2O3). The great asset ofnc-PS is its intense photoluminescence in VIS at room temperature (RT), while Ge NCs/NPs embedded in oxides show high photosensitivity in VISNIR-SWIR in the spectral photocurrent up to 1325 nm at RT. Ge NCs/NPs/QDsfloating gate NVMs present high memory performance, the retention characteristics corresponding to the state of the art for NCs floating gate NVMs. We prove the relevance of controlling the preparation parametersfor obtainingfilms with targetedphotoluminescence, photosensitivity and charge storage properties for applications, e.g. VIS-NIR-SWIR optical sensors and photodetectors, and electronic and photoelectric NVMs. We evidence the correlation of preparation conditions, morphology, composition and crystalline structure with optical, electrical, photoelectrical and charge storage properties and also evidence the contribution ofquantum confinement effect, localized States and trapping centers."

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“…If the value is below this, the process of direct tunneling of the charge carriers between the Si substrate and the floating gate layer through the SiO 2 tunneling layer leads to a high-leakage current and a low-charge retention capability of the MOS-like capacitor [4]. A solution to this problem is to replace the SiO 2 with a high-k oxide, such as ZrO 2 , HfO 2 or Al 2 O 3 [5][6][7][8][9][10][11], that has a dielectric constant of k > 20, which is sufficiently high to have a low equivalent oxide thickness (EOT) [12] and low enough to avoid the lateral fringing-field effect [13,14] to be used in MOS-like capacitors. ZrO 2 is characterized by a good interface with Si [15] and being thermally stable [16], and the temperature of the phase transformation from monoclinic to tetragonal is almost 500 • C, which is lower than that for HfO 2 [17,18].…”

Section: Introductionmentioning

confidence: 99%

Memory Properties of Zr-Doped ZrO2 MOS-like Capacitor

Palade¹,

Slav²,

Stavarache³

et al. 2022

Coatings

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The high-k-based MOS-like capacitors are a promising approach for the domain of non-volatile memory devices, which currently is limited by SiO2 technology and cannot face the rapid downsizing of the electronic device trend. In this paper, we prepare MOS-like trilayer memory structures based on high-k ZrO2 by magnetron sputtering, with a 5% and a 10% concentrations of Zr in the Zr–ZrO2 floating gate layer. For crystallization of the memory structure, rapid thermal annealing at different temperatures between 500 °C and 700 °C was performed. Additionally, Al electrodes were deposited in a top-down configuration. High-resolution transmission electron microscopy reveals that ZrO2 has a polycrystalline–columnar crystallization and a tetragonal crystalline structure, which was confirmed by X-ray diffraction measurements. It is shown that the tetragonal phase is stabilized during the crystallization by the fast diffusion of oxygen atoms. The capacitance–voltage characteristics show that the widest memory window (ΔV = 2.23 V) was obtained for samples with 10% Zr annealed at 700 °C for 4 min. The charge retention characteristics show a capacitance decrease of 36% after 10 years.

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SiGeSn Quantum Dots in HfO2 for Floating Gate Memory Capacitors

Cited by 9 publications

References 33 publications

Enhancing SiGeSn nanocrystals SWIR photosensing by high passivation in nanocrystalline HfO2 matrix

Enhancing SiGeSn nanocrystals SWIR photosensing by high passivation in nanocrystalline HfO2 matrix

FROM Si NANOWIRES TO Ge NANOCRYSTALS FOR VIS-NIR-SWIR SENSORS AND NON-VOLATILE MEMORIES: A REVIEW

Memory Properties of Zr-Doped ZrO2 MOS-like Capacitor

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