Metallization Issues in Advanced Ceramic Substrates:- Microstructural. Microchemistry and Thermal Conductivity in Aln

1989 ◽  
Vol 154 ◽  
Author(s):  
Alistair D. Westwood ◽  
Michael R. Notis
Keyword(s):  
Thermal Conductivity ◽  
Grain Boundary ◽  
Aluminum Nitride ◽  
Grain Boundaries ◽  
Thick Film ◽  
Interface Morphology ◽  
Ceramic Substrates ◽  
Microstructural Study ◽  
Boundary Film ◽  
Manganese Aluminum

AbstractMicrochemical and microstructural study has been carried out on the tungsten-aluminum nitride (W-AlN) thick film metallization interface. A reaction has been found to occur with the formation of precipitates at AlN grain boundaries and also within the AlN grains; a thin crystalline grain boundary film was also observed. The interface morphology and chemistry is compared to the molybdenum/manganese-aluminum nitride (MoMn-AlN) interface. The effects of morphology and microchemical variations upon thermal conductivity are discussed.

Improvement of thermoelectric performance of Bi2Te2.7Se0.3 via grain boundary engineering with melting KOH

2019 ◽  
Vol 12 (06) ◽  
pp. 1950082 ◽  
Author(s):  
Tingyang Liu ◽  
Weiming Zhu ◽  
Rui Wang ◽  
Shuankui Li ◽  
Yinguo Xiao
Keyword(s):  
Thermal Conductivity ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Weight Percent ◽  
Phonon Transport ◽  
Liquid Phase Sintering ◽  
Homogeneous Distribution ◽  
Grain Boundary Engineering ◽  
Sintering Process ◽  
Simple Method

Grain boundary engineering is considered an effective approach to improve the performance of thermoelectric materials. Herein, by introducing KOH into the grain boundary of Bi2[Formula: see text][Formula: see text] (BTS) via liquid phase sintering strategy, the thermoelectric performances are improved significantly. The melting KOH spreads over the grain boundaries during the high temperature sintering process, which could be used to optimize the carrier/phonon transport behavior. The maximum ZT reaches up to 0.97 for the sample incorporated with 0.5%[Formula: see text]Wt of KOH at 425[Formula: see text]K, which achieves 30% improvement over the pure BTS. The homogeneous distribution of KOH layer on the grain boundaries forms efficient potential barrier scattering, which increases power factor and reduces thermal conductivity simultaneously. Particularly, it is found that the maximum ZT can be tuned gradually in the temperature range from 450[Formula: see text]K to 375[Formula: see text]K by tuning the weight percent of KOH, demonstrating a possibility in adjusting the thermoelectric properties of BTS using a relatively simple method.

Advanced DBC - Highly Reliable and Conductive Copper Ceramic Substrates

2016 ◽  
Vol 2016 (CICMT) ◽  
pp. 000073-000078
Author(s):  
Paul Gundel ◽  
Anton Miric ◽  
Kai Herbst ◽  
Melanie Bawohl ◽  
Jessica Reitz ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Cycling ◽  
Power Electronics ◽  
Thick Film ◽  
Low Cost ◽  
Automotive Applications ◽  
Ceramic Substrates ◽  
Hybrid Technologies

Abstract So far Direct Bonded Copper (DBC) substrates have been the standard for power electronics. They provide excellent electrical and thermal conductivity at low cost. Weaknesses of DBC technology are the inevitable warpage and the relatively low reliability under thermal cycling. The low reliability poses a significant hurdle in particular for automotive applications with high lifetime requirements. Thick Print Copper (TPC) substrates with low warpage and excellent reliability overcome these weaknesses, but also provide a reduced conductivity at a higher cost. We present two thick-film/DBC hybrid technologies which combine the best properties of DBC and TPC: excellent conductivity, low cost, reduced warpage and excellent reliability.

High thermal conductivity aluminum nitride ceramic substrates and packages

1990 ◽  
Vol 13 (2) ◽  
pp. 313-319 ◽  
Author(s):  
F. Miyashiro ◽  
N. Iwase ◽  
A. Tsuge ◽  
F. Ueno ◽  
M. Nakahashi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Aluminum Nitride ◽  
High Thermal Conductivity ◽  
Ceramic Substrates

Effect of grain-boundary stabilization on the strength, thermal conductivity, and dielectric properties of aluminum nitride

2000 ◽  
Vol 36 (5) ◽  
pp. 504-507 ◽  
Author(s):  
S. N. Ivanov ◽  
L. M. Zhukova ◽  
Ya. M. Soifer ◽  
E. N. Khazanov ◽  
A. V. Taranov
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Properties ◽  
Grain Boundary ◽  
Aluminum Nitride ◽  
Boundary Stabilization

Systematic over-estimation of lattice thermal conductivity in materials with electrically-resistive grain boundaries

2020 ◽  
Vol 13 (4) ◽  
pp. 1250-1258 ◽  
Author(s):  
Jimmy Jiahong Kuo ◽  
Max Wood ◽  
Tyler J. Slade ◽  
Mercouri G. Kanatzidis ◽  
G. Jeffrey Snyder
Keyword(s):  
Thermal Conductivity ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Electrical Resistance ◽  
Carrier Mobility ◽  
Lattice Thermal Conductivity ◽  
Transport Model ◽  
Two Phase ◽  
Phase Transport

The inverse trend between carrier mobility and lattice thermal conductivity is found to be an artifact of grain boundary electrical resistance. A two-phase transport model is required to properly account for the effect.

Grain Boundaries in High Thermal Conductivity Aluminum Nitride.

1990 ◽  
Vol 203 ◽  
Author(s):  
Stuart Mckernan ◽  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thermal Conductivity ◽  
Aluminum Nitride ◽  
Grain Boundaries ◽  
Polycrystalline Material ◽  
Electronics Packaging ◽  
Substrate Material ◽  
High Thermal Conductivity ◽  
Different Types ◽  
Packaging Industry ◽  
Complementary Techniques

ABSTRACTThe benefits of AIN as a substrate material for the electronics packaging industry appear to be limited by the deleterious effects of boundaries in the polycrystalline material. Some observations on different types of boundary in AIN using several complementary techniques are reported.

Measurement of the Displacement Across a Coincidence Grain Boundary

1977 ◽  
Vol 35 ◽  
pp. 124-125
Author(s):  
J. W. Matthews ◽  
W. M. Stobbs
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Stacking Fault ◽  
The Other ◽  
Measuring Technique ◽  
High Angle ◽  
Twin Boundaries ◽  
Rigid Displacement ◽  
Cubic Crystals ◽  
Lattice Displacement

Many high-angle grain boundaries in cubic crystals are thought to be either coincidence boundaries (1) or coincidence boundaries to which grain boundary dislocations have been added (1,2). Calculations of the arrangement of atoms inside coincidence boundaries suggest that the coincidence lattice will usually not be continuous across a coincidence boundary (3). There will usually be a rigid displacement of the lattice on one side of the boundary relative to that on the other. This displacement gives rise to a stacking fault in the coincidence lattice.Recently, Pond (4) and Smith (5) have measured the lattice displacement at coincidence boundaries in aluminum. We have developed (6) an alternative to the measuring technique used by them, and have used it to find two of the three components of the displacement at {112} lateral twin boundaries in gold. This paper describes our method and presents a brief account of the results we have obtained.

Observations of dislocation interactions with recrystallized grain boundaries

1988 ◽  
Vol 46 ◽  
pp. 628-629
Author(s):  
C. W. Price
Keyword(s):  
Dislocation Density ◽  
Grain Boundary ◽  
Strain Rate ◽  
Grain Boundaries ◽  
Dislocation Structure ◽  
Hot Deformation ◽  
Static Recrystallization ◽  
High Dislocation Density ◽  
High Angle ◽  
Dislocation Interactions

Little evidence exists on the interaction of individual dislocations with recrystallized grain boundaries, primarily because of the severely overlapping contrast of the high dislocation density usually present during recrystallization. Interesting evidence of such interaction, Fig. 1, was discovered during examination of some old work on the hot deformation of Al-4.64 Cu. The specimen was deformed in a programmable thermomechanical instrument at 527 C and a strain rate of 25 cm/cm/s to a strain of 0.7. Static recrystallization occurred during a post anneal of 23 s also at 527 C. The figure shows evidence of dissociation of a subboundary at an intersection with a recrystallized high-angle grain boundary. At least one set of dislocations appears to be out of contrast in Fig. 1, and a grainboundary precipitate also is visible. Unfortunately, only subgrain sizes were of interest at the time the micrograph was recorded, and no attempt was made to analyze the dislocation structure.

Measurement of solute segregation to grain boundaries in the AEM: A review

1988 ◽  
Vol 46 ◽  
pp. 606-607
Author(s):  
D. B. Williams ◽  
A. D. Romig
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Boundary Misorientation ◽  
Collector Plate ◽  
Segregation Process ◽  
Grain Boundary Misorientation ◽  
Structure Boundary ◽  
Equilibrium Segregation

The segregation of solute or imparity elements to grain boundaries can occur by three well-defined processes. The first is Gibbsian segregation in which an element of minimal matrix solubility confines itself to a monolayer at the grain boundary. Classical examples include Bi in Cu and S or P in Fe. The second process involves the depletion of excess matrix solute by volume diffusion to the boundary. In the boundary, the solute atoms diffuse rapidly to precipitates, causing them to grow by the ‘collector-plate mechanism.’ Such grain boundary diffusion is thought to initiate “Diffusion-Induced Grain Boundary Migration,” (DIGM). This process has been proposed as the origin of eutectoid transformations or discontinuous grain boundary reactions. The third segregation process is non-equilibrium segregation which result in a solute build-up around the boundary because of solute-vacancy interactions.All of these segregation phenomena usually occur on a sub-micron scale and are often affected by the nature of the grain boundary (misorientation, defect structure, boundary plane).

Sign in / Sign up

Export Citation Format

Share Document