Development of high-thermal-conductivity silicon nitride ceramics

Abstract

a b s t r a c tSilicon nitride (Si 3 N 4 ) with high thermal conductivity has emerged as one of the most promising substrate materials for the next-generation power devices. This paper gives an overview on recent developments in preparing high-thermal-conductivity Si 3 N 4 by a sintering of reaction-bonded silicon nitride (SRBSN) method. Due to the reduction of lattice oxygen content, the SRBSN ceramics could attain substantially higher thermal conductivities than the Si 3 N 4 ceramics prepared by the conventional gas-pressure sintering of silicon nitride (SSN) method. Thermal conductivity could further be improved through increasing the ␤/␣ phase ratio during nitridation and enhancing grain growth during post-sintering. Studies on fracture resistance behaviors of the SRBSN ceramics revealed that they possessed high fracture toughness and exhibited obvious R-curve behaviors. Using the SRBSN method, a Si 3 N 4 with a record-high thermal conductivity of 177 Wm −1 K −1 and a fracture toughness of 11.2 MPa m 1/2 was developed. Studies on the influences of two typical metallic impurity elements, Fe and Al, on thermal conductivities of the SRBSN ceramics revealed that the tolerable content limits for the two impurities were different. While 1 wt% of impurity Fe hardly degraded thermal conductivity, only 0.01 wt% of Al caused large decrease in thermal conductivity.

ZrSi2–MgO as novel additives for high thermal conductivity of β‐Si3N4 ceramics

“…For one thing, oxygen dissolution into the lattice can be inhibited by using additives with high oxygen affinity, and raw materials with low oxygen content . For another, the lattice oxygen can be efficiently removed by increasing sintering and annealing time via the dissolution‐precipitation process . In addition to the lattice oxygen, high thermal conductivity of β‐Si 3 N 4 can be achieved by tailoring microstructural factors, such as grain size, grain orientation, and intergranular secondary phases(composition, amount, and distribution) .…”

Studies on Preparation and Characterization of Aluminum Nitride-Coated Carbon Fibers and Thermal Conductivity of Epoxy Matrix Composites

“…Coatings 2017, 7,121 crystallites. Figure 3 shows that as the reaction temperature increases, the (100) peak of XRD and AlN products formation is completed.…”

“…Normally, high thermal conductive performance has been obtained by adding fillers due to the thermal conductive chains or networks produced by the fillers [1][2][3][4][5]. In order to improve the thermal conductivity of composites, various inorganic ceramic fillers with high thermal conductivity have been introduced into insulation composites; notable example include silicon nitride (SiN) [6][7][8], silicon carbide (SiC) [9], boron nitride (BN) [10,11], alumina oxide (Al 2 O 3 ) [12][13][14], and alumina nitride (AlN) [15][16][17]. Among the various ceramic fillers, aluminum nitride is an important ceramic material that has attracted considerable attention due to its excellent thermal conductivity (82-170 W/mK) and electrical resistance (>10 14 Ω·cm @ R.T.), as well as its high density, wide band gap, low dielectric constant, and low thermal expansion coefficient close to that of silicon [18][19][20][21][22][23][24][25][26][27][28].…”

Combustion synthesis of MgSiN2 powders and Si3N4‐MgSiN2 composite powders: Effects of processing parameters

“…High‐thermal conductivity Si 3 N 4 ‐based ceramics have attracted increasing attention in recent years owing to the prospect of being used as electronic packaging materials . The highest thermal conductivity of Si 3 N 4 ‐based ceramics was reported as 177 W m −1 K −1 , whereas the value is much lower than the calculated one (about 170 W m −1 K −1 along a ‐axis and 450 W m −1 K −1 along c ‐axis) . According to early studies, lattice oxygen content is one of the most important factors that can have a negative impact on the thermal conductivity of Si 3 N 4 ‐based ceramics .…”