scholarly journals Ultimate suppression of thermal transport in amorphous silicon nitride by phononic nanostructure

2020 ◽  
Vol 6 (39) ◽  
pp. eabc0075
Author(s):  
Naoki Tambo ◽  
Yuxuan Liao ◽  
Chun Zhou ◽  
Elizabeth Michiko Ashley ◽  
Kouhei Takahashi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Thermal Transport ◽  
Amorphous Materials ◽  
Vibrational Modes ◽  
Amorphous Silicon Nitride ◽  
Diffusive Boundary ◽  
20 Nm ◽  
The Impact

Engineering the thermal conductivity of amorphous materials is highly essential for the thermal management of future electronic devices. Here, we demonstrate the impact of ultrafine nanostructuring on the thermal conductivity reduction of amorphous silicon nitride (a-Si3N4) thin films, in which the thermal transport is inherently impeded by the atomic disorders. Ultrafine nanostructuring with feature sizes below 20 nm allows us to fully suppress contribution of the propagating vibrational modes (propagons), leaving only the diffusive vibrational modes (diffusons) to contribute to thermal transport in a-Si3N4. A combination of the phonon-gas kinetics model and the Allen-Feldmann theory reproduced the measured results without any fitting parameters. The thermal conductivity reduction was explained as extremely strong diffusive boundary scattering of both propagons and diffusons. These findings give rise to substantial tunability of thermal conductivity of amorphous materials, which enables us to provide better thermal solutions in microelectronic devices.

scholarly journals Hydrogen effects on the thermal conductivity of delocalized vibrational modes in amorphous silicon nitride (a−SiNx:H)

2021 ◽  
Vol 5 (3) ◽  
Author(s):  
Jeffrey L. Braun ◽  
Sean W. King ◽  
Eric R. Hoglund ◽  
Mehrdad Abbasi Gharacheh ◽  
Ethan A. Scott ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Vibrational Modes ◽  
Amorphous Silicon Nitride

Enhanced crystallization and phase transformation of amorphous silicon nitride under high pressure

2001 ◽  
Vol 16 (1) ◽  
pp. 67-75 ◽  
Author(s):  
Ya-Li Li ◽  
Yong Liang ◽  
Fen Zheng ◽  
Xian-Feng Ma ◽  
Suo-Jing Cui ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transformation ◽  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Crystallization Temperature ◽  
Amorphous Materials ◽  
Normal Pressure ◽  
Nucleation And Growth ◽  
Amorphous Silicon Nitride ◽  
Amorphous Si

The crystallization and phase transformation of amorphous Si3N4 ceramics under high pressure (1.0–5.0 GPa) between 800 and 1700 °C were investigated. A greatly enhanced crystallization and α–β transformation of the amorphous Si3N4 ceramics were evident under the high pressure, as characterized by that, at 5.0 GPa, the amorphous Si3N4 began to crystallize at a temperature as low as 1000 °C (to transform to a modification). The subsequent a–b transformation occurred completed between 1350 and 1420 °C after only 20 min of pressing at 5.0 GPa. In contrast, under 0.1 MPa N2, the identical amorphous materials were stable up to 1400 °C without detectable crystallization, and only a small amount of a phase was detected at 1500 °C. The crystallization temperature and the a–b transformation temperatures are reduced by 200–350 °C compared to that at normal pressure. The enhanced phase transformations of the amorphous Si3N4 were discussed on the basis of thermodynamic and kinetic consideration of the effects of pressure on nucleation and growth.

Structure, Mechanical Properties, and Thermal Transport in Microporous Silicon Nitride Via Parallel Molecular Dynamics

1995 ◽  
Vol 408 ◽  
Author(s):  
Andrey Omeltchenko ◽  
Aiichiro Nakano ◽  
Rajiv K. Kalia ◽  
Priya Vashishta
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Silicon Nitride ◽  
Elastic Constants ◽  
Thermal Transport ◽  
Entire System ◽  
Amorphous Silicon Nitride ◽  
Parallel Molecular Dynamics ◽  
Dynamics Simulations

AbstractMolecular dynamics simulations are performed to investigate structure, mechanical properties, and thermal transport in amorphous silicon nitride under uniform dilation. As the density is lowered, we observe the formation of pores below ρ = 2.6 g/cc and at 2.0 g/cc the largest pore percolates through the entire system. Effects of porosity on elastic constants, phonons and thermal conductivity are investigated. Thermal conductivity and Young's modulus are found to scale as ρ1.5 and ρ3.6, respectively.

Enhanced Reduction of Thermal Conductivity in Amorphous Silicon Nitride-Containing Phononic Crystals Fabricated Using Directed Self-Assembly of Block Copolymers

ACS Nano ◽  
2020 ◽  
Vol 14 (6) ◽  
pp. 6980-6989 ◽  
Author(s):  
Chun Zhou ◽  
Naoki Tambo ◽  
Elizabeth Michiko Ashley ◽  
Yuxuan Liao ◽  
Junichiro Shiomi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Silicon Nitride ◽  
Block Copolymers ◽  
Amorphous Silicon ◽  
Self Assembly ◽  
Phononic Crystals ◽  
Amorphous Silicon Nitride

scholarly journals Effect of Thermal Annealing on the Photoluminescence of Dense Si Nanodots Embedded in Amorphous Silicon Nitride Films

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 354
Author(s):  
Qianqian Liu ◽  
Xiaoxuan Chen ◽  
Hongliang Li ◽  
Yanqing Guo ◽  
Jie Song ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Thermal Annealing ◽  
Chemical Vapor ◽  
Peak Position ◽  
Excitation Wavelength ◽  
Very High Frequency ◽  
Amorphous Silicon Nitride ◽  
Silicon Nitride Films ◽  
High Frequency Plasma

Luminescent amorphous silicon nitride-containing dense Si nanodots were prepared by using very-high-frequency plasma-enhanced chemical vapor deposition at 250 °C. The influence of thermal annealing on photoluminescence (PL) was studied. Compared with the pristine film, thermal annealing at 1000 °C gave rise to a significant enhancement by more than twofold in terms of PL intensity. The PL featured a nanosecond recombination dynamic. The PL peak position was independent of the excitation wavelength and measured temperatures. By combining the Raman spectra and infrared absorption spectra analyses, the enhanced PL was suggested to be from the increased density of radiative centers related to the Si dangling bonds (K0) and N4+ or N20 as a result of bonding configuration reconstruction.

Kinetics of silicon nitride crystallization in N+-implanted silicon

1989 ◽  
Vol 4 (2) ◽  
pp. 394-398 ◽  
Author(s):  
V. S. Kaushik ◽  
A. K. Datye ◽  
D. L. Kendall ◽  
B. Martinez-Tovar ◽  
D. S. Simons ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Crystalline Silicon ◽  
Wafer Surface ◽  
Amorphous Silicon Nitride ◽  
Silicon Lattice ◽  
Nitrogen Ions ◽  
The Mean ◽  
Nitride Layers ◽  
Kinetics Of

Implantation of nitrogen at 150 KeV and a dose of 1 ⊠ 1018/cm2 into (110) silicon results in the formation of an amorphized layer at the mean ion range, and a deeper tail of nitrogen ions. Annealing studies show that the amorphized layer recrystallizes into a continuous polycrystalline Si3N4 layer after annealing for 1 h at 1200 °C. In contrast, the deeper nitrogen fraction forms discrete precipitates (located 1μm below the wafer surface) in less than 1 min at this temperature. The arcal density of these precipitates is 5 ⊠ 107/cm2 compared with a nuclei density of 1.6 ⊠ 105/cm2 in the amorphized layer at comparable annealing times. These data suggest that the nucleation step limits the recrystallization rate of amorphous silicon nitride to form continuous buried nitride layers. The nitrogen located within the damaged crystalline silicon lattice precipitates very rapidly, yielding semicoherent crystallites of β–Si3N4.

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