Numerical Study on the Laser Annealing of Silicon Used in Advanced V-NAND Device

Son, Yeong-Il; Shin, Jungyeop

doi:10.3390/ma15124201

Cited by 4 publications

(3 citation statements)

References 36 publications

(34 reference statements)

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“…The above results show that the top silicon of the “exposed vertical nanosheet” changed from having a right-angled surface to a curved surface. This result shows that the top silicon of the nanosheet underwent a recrystallization process of “a-Si (solid)-Si (liquid)-c-Si (solid)” [ 20 , 21 ]. Moreover, it can be seen that the surface morphology of the ring-shaped recrystallized nanosheet was relatively uniform, and no apparent cracks appeared.…”

Section: Resultsmentioning

confidence: 99%

High-Quality Recrystallization of Amorphous Silicon on Si (100) Induced via Laser Annealing at the Nanoscale

Chen

Zhu

Wang³

et al. 2023

Nanomaterials

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At sub-3 nm nodes, the scaling of lateral devices represented by a fin field-effect transistor (FinFET) and gate-all-around field effect transistors (GAAFET) faces increasing technical challenges. At the same time, the development of vertical devices in the three-dimensional direction has excellent potential for scaling. However, existing vertical devices face two technical challenges: “self-alignment of gate and channel” and “precise gate length control”. A recrystallization-based vertical C-shaped-channel nanosheet field effect transistor (RC-VCNFET) was proposed, and related process modules were developed. The vertical nanosheet with an “exposed top” structure was successfully fabricated. Moreover, through physical characterization methods such as scanning electron microscopy (SEM), atomic force microscopy (AFM), conductive atomic force microscopy (C-AFM) and transmission electron microscopy (TEM), the influencing factors of the crystal structure of the vertical nanosheet were analyzed. This lays the foundation for fabricating high-performance and low-cost RC-VCNFETs devices in the future.

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Section: Resultsmentioning

confidence: 99%

High-Quality Recrystallization of Amorphous Silicon on Si (100) Induced via Laser Annealing at the Nanoscale

Chen

Zhu

Wang³

et al. 2023

Nanomaterials

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“…While in 3D NAND Flash, Lisoni et al proposed the use of LTA to crystallize amorphous silicon channel in vertical channel transistors [ 20 ], thus optimizing the grain size. Son et al used numerical simulation to study the laser conditions with multipath and beam overlap to improve temperature uniformity within the annealed area [ 21 ]. However, channel dopant activation in vertical transistors has not been studied.…”

Section: Introductionmentioning

confidence: 99%

Activation Enhancement and Grain Size Improvement for Poly-Si Channel Vertical Transistor by Laser Thermal Annealing in 3D NAND Flash

et al. 2023

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The bit density is generally increased by stacking more layers in 3D NAND Flash. Lowering dopant activation of select transistors results from complex integrated processes. To improve channel dopant activation, the test structure of vertical channel transistors was used to investigate the influence of laser thermal annealing on dopant activation. The activation of channel doping by different thermal annealing methods was compared. The laser thermal annealing enhanced the channel activation rate by at least 23% more than limited temperature rapid thermal annealing. We then comprehensively explore the laser thermal annealing energy density on the influence of Poly-Si grain size and device performance. A clear correlation between grain size mean and grain size sigma, large grain size mean and sigma with large laser thermal annealing energy density. Large laser thermal annealing energy density leads to tightening threshold voltage and subthreshold swing distribution since Poly-Si grain size regrows for better grain size distribution with local grains optimization. As an enabler for next-generation technologies, laser thermal annealing will be highly applied in 3D NAND Flash for better device performance with stacking more layers, and opening new opportunities of novel 3D architectures in the semiconductor industry.

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“…The laser annealing procedure has been widely used for recrystallization and surface treatments in many applications. For instance, Son et al [ 26 ] investigated the laser melt annealing of amorphous silicon (a-Si) and the subsequent recrystallization of a-Si for successfully implementing vertical flash memory devices. In another work, Novotny et al [ 27 ] used pulsed laser annealing on Eu-doped ZnO, TiO 2 , and Lu 2 O 3 thin films, and they measured in situ the photoluminescence and transmittance of the devices during the annealing.…”

Section: Introductionmentioning

confidence: 99%

Microcrystallization Effects Induced by Laser Annealing in Cr-Al-C Ion-Beam-Sputtered Films

Crisan

2022

Nanomaterials

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The microcrystallization effects induced by the real-time laser annealing in Cr-Al-C ion-sputtered films with an off-stoichiometric composition are studied. The laser annealing has been performed during Raman experiments with tunable laser power densities. Morphostructural changes induced during laser annealing were investigated by scanning electron microscopy. It has been proven that real-time laser annealing in the high-laser-power-density mode promotes quite clearly the formation of nanograins through surface microcrystallization. Detailed Raman analysis allowed for the observation of the optical modes that unequivocally identifies the low-symmetry 211 MAX phase in both low- and high-power-density modes. Such findings confirming the microcrystallization as well as the stabilization of the grain boundaries by carbon nanoclustering are confirmed by X-ray diffraction results, where the single-phase hexagonal 211 was unequivocally proven to form in the high-laser-power-density mode. The microcrystallization via laser annealing was also found to be beneficial for the elastic behavior, as the hardness values between 16 and 26 GPa were found after laser annealing, accompanied by a significantly high Young’s bulk modulus. Such large values, larger than those in bulk compounds, are explicable by the nanometric grain sizes accompanied by the increase of the grain boundary regions.

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Numerical Study on the Laser Annealing of Silicon Used in Advanced V-NAND Device

Cited by 4 publications

References 36 publications

High-Quality Recrystallization of Amorphous Silicon on Si (100) Induced via Laser Annealing at the Nanoscale

High-Quality Recrystallization of Amorphous Silicon on Si (100) Induced via Laser Annealing at the Nanoscale

Activation Enhancement and Grain Size Improvement for Poly-Si Channel Vertical Transistor by Laser Thermal Annealing in 3D NAND Flash

Microcrystallization Effects Induced by Laser Annealing in Cr-Al-C Ion-Beam-Sputtered Films

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