Numerical and experimental studies on synthesis of ultrafine nanosize powders of AlN by ion beam evaporation

Abstract

Synthesis of ultrafine nanosize powders by ion beam evaporation (IBE) has been studied numerically and experimentally. Theoretical models have been developed, which involve such physical processes as beam-target interaction, plasma expansion, and the synthesis of powders. The macroscopic properties of the ultrafine powders have been predicted. As an application of our models, the macroscopic properties of AlN powders synthesized by IBE with an AlN target have been predicted. The energy density, pulse width, and spot size of the ion beam are 20 J/cm2, 70 ns, and 1 cm2, respectively. The main results have shown that the particle size distribution is log normal and that 70% of all particles exist between 20 and 40 nm. The average diameter and the specific surface area are ∼30 nm and ∼50 m2/g, respectively. Experimentally, the ultrafine AlN powders have been successfully synthesized by IBE, which has been verified by x-ray diffraction and transmission electron diffraction. Furthermore, particle size distributions have been obtained by transmission electron microscopy. The experimental results are found to be in a reasonable agreement with the numerical studies.

Plasma synthesis and characterization of nanocrystalline aluminum nitride particles by aluminum plasma jet discharge

“…Nanostructured AlN particles are difficult to produce by conventional mechanical processing. Therefore, a number of processes have been developed for producing nanosized AlN powders such as pulsed laser ablation techniques [2,3], ion beam evaporation of bulk AlN [4], electrical explosion of aluminum wire [5], transferred plasma arc process [6,7], chemical vapor deposition using the AlCl 3 -NH 3 -N 2 system [8], DC arc discharge plasma evaporation of aluminum [9], and carbothermal reduction-nitridation technique [10].…”

Fabrication of Densely Packed AlN Nanowires by a Chemical Conversion of Al2O3Nanowires Based on Porous Anodic Alumina Film

“…In past few decades, aluminum nitride (AlN) has attracted considerable interests because of its exceptional mechanical, thermal, electrical, and optical properties [ 1 - 4 ]. For example, its good thermal conductivity, low dielectric constant, and high electrical resistance as well as thermal expansion coefficient matching to that of silicon offer an application in semiconductor devices as passivation and dielectric layers, and electric substrates [ 5 - 10 ]. Also, as one of wide band-gap semiconductors, aluminum nitride has a promising candidate for optoelectronic and field-emission materials [ 11 , 12 ].…”

Synthesis of hexagonal AlN microbelts at low temperature

“…Its resistivity (>10 11 m) is very high, while its dielectric constant (8.6) is very low. Due to these properties, AlN is ideal for use of electronic substrate material and integrated circuit packaging material [2]. It has high thermal conductivity (320 W m −1 K −1 ) [3], which is three times as high as that of Al 2 O 3 which is of the highest value among the ceramic materials ever found, and it has low coefficient of thermal expansion (4.3 × 10 −6 K −1 ), so AlN can be used to solve the problem of thermal matching between the substrate and the semiconductor, and the cooling problem of high power electronic devices caused by the integration and micromation [4].…”