Substrate influence on the high-temperature annealing behavior of GaN: Si vs sapphire

2005 ◽  
Vol 892 ◽  
Author(s):  
David Pastor ◽  
Ramon Cuscó ◽  
Luis Artús ◽  
Enrique Iborra ◽  
Juan Jiménez ◽  
...  
Keyword(s):  
High Temperature ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
High Concentration ◽  
Annealing Behavior ◽  
Annealing Effects ◽  
Micron Diameter ◽  
Confocal Images ◽  
High Temperature Processing ◽  
Substrate Influence

AbstractWe have studied the effects of rapid thermal annealing at 1300°C on GaN epilayers grown on AlN buffered Si(111) and on sapphire substrates. After annealing, the epilayers grown on Si display a stained surface. Scanning electron microscopy and optical confocal images revealed the presence of crater-shaped inhomogeneities that develop around protruding nuclei with tipically 50 micron diameter. Energy dispersive x-ray microanalysis yields a high concentration of Si in the crater regions as well as non-stoichiometric concentrations of Ga and N, with an excess of N.Micro-Raman spectra obtained within the crater region exhibit Raman peaks associated with Si3N4 but no trace of GaN modes, while focused ion beam milling of this region leads to the accumulation of metallic Ga in the etched area. These results suggest that a substantial migration of Si from the substrate takes place during the annealing, which severely alters the material in the crater regions. Such annealing effects, which are not observed in GaN grown on sapphire, constitute a severe drawback for a widespread use of Si(111) substrates when high-temperature processing is required.

Reduction of Whisker-Originated Short between W Polymetal and Contact Plug

2001 ◽  
Vol 670 ◽  
Author(s):  
Yasushi Akasaka ◽  
Hiroshi Suzuki ◽  
Yuji Yokoyama ◽  
Nobuaki Yasutake ◽  
Hitomi Yasutake ◽  
...  
Keyword(s):  
High Temperature ◽  
Leakage Current ◽  
Focused Ion Beam ◽  
Whisker Growth ◽  
Ion Beam ◽  
The Self ◽  
Cross Sectional ◽  
Gate Electrodes ◽  
High Temperature Processing ◽  
First Time

ABSTRACTWhisker-originated short in the self-aligned contact (SAC) W polymetal gate was directly observed for the first time. Short points between gate electrodes and poly-Si plugs in the test structure were identified by emission microscope and cross-sectional TEM samples of those points were made by using focused ion beam (FIB).Whiskers are formed during high-temperature processing such as LP-CVD SiN. We have proposed that NH3 de-oxidation step inserted in the SiN deposition sequence is effective for suppressing whisker growth. [1] In this study it was also confirmed that 600°C NH 3 pre-flow improved leakage current between gate electrode and contact plugs.

Nanocomposite Polyurethane Foams Via POSS Blends

2002 ◽  
Vol 733 ◽  
Author(s):  
Brock McCabe ◽  
Steven Nutt ◽  
Brent Viers ◽  
Tim Haddad
Keyword(s):  
High Temperature ◽  
Sample Preparation ◽  
Room Temperature ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Polyurethane Foams ◽  
Development Projects ◽  
Polymer Systems ◽  
Polyurethane Resin ◽  
Military Development

AbstractPolyhedral Oligomeric Silsequioxane molecules have been incorporated into a commercial polyurethane formulation to produce nanocomposite polyurethane foam. This tiny POSS silica molecule has been used successfully to enhance the performance of polymer systems using co-polymerization and blend strategies. In our investigation, we chose a high-temperature MDI Polyurethane resin foam currently used in military development projects. For the nanofiller, or “blend”, Cp7T7(OH)3 POSS was chosen. Structural characterization was accomplished by TEM and SEM to determine POSS dispersion and cell morphology, respectively. Thermal behavior was investigated by TGA. Two methods of TEM sample preparation were employed, Focused Ion Beam and Ultramicrotomy (room temperature).

Ion Implantation and Annealing Effects in Silicon Carbide

1996 ◽  
Vol 438 ◽  
Author(s):  
V. Heera ◽  
W. Skorupa
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Ion Implantation ◽  
High Power ◽  
High Frequency ◽  
Ion Beam ◽  
Surface Erosion ◽  
Annealing Effects ◽  
Ion Ranges ◽  
Induced Crystallization

AbstractSiC is a promising semiconductor material for high-power/high-frequency and hightemperature electronic applications. For selective doping of SiC ion implantation is the only possible process. However, relatively little is known about ion implantation and annealing effects in SiC. Compared to ion implantation into Si there is a number of specific features which have to be considered for successful ion beam processing of SiC. A brief review is given on some aspects of ion implantation in and annealing of SiC. The ion implantation effects in SiC are discussed in direct comparison to Si. The following issues are addressed: ion ranges, radiation damage, amorphization, high temperature implantation, ion beim induced crystallization and surface erosion.

Estimation of the High-Temperature R Curve for Ceramics from Strength Measurements Including Specimens with Focused Ion Beam Notches

2010 ◽  
Vol 93 (9) ◽  
pp. 2411-2414 ◽  
Author(s):  
Stefan Fünfschilling ◽  
Theo Fett ◽  
Michael J. Hoffmann ◽  
Rainer Oberacker ◽  
Hüseyin Özcoban ◽  
...  
Keyword(s):  
High Temperature ◽  
Focused Ion Beam ◽  
Ion Beam

scholarly journals Failure Analysis of Wire Bonding on Strain Gauge Contact Pads Using FIB, SEM, and Elemental Mapping

2021 ◽  
Vol 6 (1) ◽  
pp. 53
Author(s):  
Muhammad Talal Asghar ◽  
Thomas Frank ◽  
Frank Schwierz
Keyword(s):  
High Temperature ◽  
Strain Gauge ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Wire Bonding ◽  
Elemental Mapping ◽  
Sintering Process ◽  
Height Difference ◽  
Root Cause ◽  
Bond Pads

Stacks consisting of titanium, platinum, and gold layers constitute a popular metallization system for the bond pads of semiconductor chips. Wire bonding on such layer stacks at different temperatures has extensively been investigated in the past. However, reliable information on the bondability of this metallization system after a high-temperature sintering process is still missing. When performing wire bonding after pressure sintering (at, e.g., 875 °C), bonding failures may occur that must be identified and analyzed. In the present study, a focused ion beam (FIB), scanning electron microscopy (SEM), and elemental mapping are utilized to characterize the root cause of failure. As a probable root cause, the infusion of metallization layers is found which causes an agglomerate formation at the interface of approximately 2 μm height difference on strain gauge contact pads and possibly an inhomogeneous mixing of layers as a consequence of the high-temperature sintering process. Potential treatment to tackle this agglomeration with the removal of the above-mentioned height difference during the process of contact pad structuring and alternative electrical interconnect methodologies are hereby suggested in this paper.

High Temperature Reliability of Copper Wire - Bonded Packages Encapsulated with Mold Compounds Containing Sulfur compounds

2014 ◽  
Vol 2014 (1) ◽  
pp. 000477-000482
Author(s):  
Varughese Mathew ◽  
Sheila Chopin
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Focused Ion Beam ◽  
Copper Wire ◽  
Ion Beam ◽  
Sulfur Compounds ◽  
Anionic Species ◽  
Headspace Concentration ◽  
Compound Matrix ◽  
Gas Chromatography Mass Spectroscopy

Copper wire-bonded (CuWB) packaging is more susceptible to corrosion than traditional inert gold wires. CuWB reliability greatly depends on the compatibility of Cu wire with the surrounding encapsulating mold compound as this matrix can provide a corrosive environment leading to reliability issues. Many mold compounds contain specific components which are sulfur-based compounds. Since the reliability testing of an encapsulated packaged device involves thermal treatments such as high temperature storage life (HTSL) test, there is a concern that corrosive sulfur compounds can be produced at high temperatures, e.g. 150 °C and 175 °C, endangering CuWB reliability. This paper describes methods of detection of sulfur compounds produced from mold compounds, if any, at high temperatures such as 175 °C and CuWB die package reliability with mold compounds containing sulfur compounds. Dynamic Headspace Concentration-Gas Chromatography–Mass Spectroscopy (DHC-GC-MS) analysis technique was used to test liberation of gaseous and volatile sulfur compounds from mold compounds at temperatures 25 °C, 150 °C, 175 °C, and 200 °C. No gaseous sulfur compounds were detected by chromatographic methods within the time period of the experiments. In order to determine sulfur containing anionic species present in the mold compound matrix, such as sulfide, sulfite, sulfate and thiosulfate, ionic compounds were extracted to water and analyzed by Ion Chromatography. Upon analysis, the only sulfur bearing anion found in the samples was sulfate. Thermally treated mold compounds for 2000 hours at 150 °C and 1000 hours at 175 °C were also extracted and analyzed to determine possible decomposition of sulfur compounds due to the thermal aging process. Corrosion due to sulfur compounds and reliability of CuWB (bare Cu-25 μm wire diameter) were evaluated by HTSL for 2000 hours at temperatures of 150 °C and 175 °C with devices packaged with mold compounds containing sulfur compounds. CuWB ball bond – Al interface and Cu stitch bond integrity were evaluated by FIB (Focused Ion Beam) - SEM (Scanning Electron Microscope) with EDX (energy dispersive X-ray spectrometer) analysis and wire pull and ball shear testing of CuWB ball bonds. No reliability issues due to sulfur compounds were found with mold compounds containing sulfates up to about 45 ppm.

High-Temperature Reliability of Copper Wire-Bonded Packages Encapsulated with Mold Compounds Containing Sulfur Compounds

2015 ◽  
Vol 12 (4) ◽  
pp. 226-231 ◽  
Author(s):  
Varughese Mathew ◽  
Sheila Chopin
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Focused Ion Beam ◽  
Copper Wire ◽  
Ion Beam ◽  
Sulfur Compounds ◽  
Detection Methods ◽  
Anionic Species ◽  
Headspace Concentration ◽  
Gas Chromatography Mass Spectroscopy

Cu wire-bonded (CuWB) packaging is more susceptible to corrosion than traditional inert gold wires. CuWB reliability greatly depends on the compatibility of Cu wire with the surrounding encapsulating mold compound as this matrix can provide a corrosive environment leading to reliability issues. Many mold compounds contain specific components, which are sulfur-based compounds. Since the reliability testing of an encapsulated packaged device involves thermal treatments, such as the high-temperature storage life (HTSL) test, there is a concern that corrosive sulfur compounds can be produced at high temperatures (e.g., 150°C and 175°C), endangering CuWB reliability. This article describes detection methods of sulfur compounds produced from mold compounds, if any, at high temperatures such as 175°C and CuWB die package reliability with mold compounds containing sulfur compounds. The dynamic headspace concentration-gas chromatography-mass spectroscopy analysis technique was used to test liberation of gaseous and volatile sulfur compounds from mold compounds at temperatures 25°C, 150°C, 175°C, and 200°C. No gaseous sulfur compounds were detected by chromatographic methods within the time period of the experiments. To determine sulfur-containing anionic species present in the mold compound matrix, such as sulfide, sulfite, sulfate, and thiosulfate, ionic compounds were extracted to water and analyzed by ion chromatography. Upon analysis, the only sulfur-bearing anion found in the samples was sulfate. Thermally treated mold compounds for 2,000 h at 150°C and for 1,000 h at 175°C were also extracted and analyzed to determine possible decomposition of sulfur compounds due to the thermal aging process. Corrosion due to sulfur compounds and reliability of CuWB was evaluated by HTSL for 2,000 h at temperatures of 150°C and 175°C with devices packaged with mold compounds containing sulfur compounds. CuWB ball bond-Al interface and Cu stitch bond integrity were evaluated by focused ion beam-scanning electron microscopy with energy-dispersive x-ray spectroscopic analysis and wire pull and ball shear testing of CuWB ball bonds. No reliability issues due to sulfur compounds were found with mold compounds containing sulfates up to ∼45 ppm.

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