Enhanced Diffusion of High-Temperature Implanted Aluminum in Silicon Carbide

1995 ◽  
Vol 396 ◽  
Author(s):  
A V. Suvorov ◽  
I.O. Usov ◽  
V.V. Sokolov ◽  
A.A. Suvorova
Keyword(s):  
Silicon Carbide ◽  
Diffusion Coefficient ◽  
High Temperature ◽  
Secondary Ion Mass Spectrometry ◽  
Near Surface ◽  
Enhanced Diffusion ◽  
Thermally Activated ◽  
Transmission Electron ◽  
Radiation Enhanced Diffusion ◽  
Sic Wafer

AbstractThe diffusion of aluminum in silicon carbide during high-temperature A1+ ion implantation was studied using secondary ion mass spectrometry (SIMS). Transmission electron microscopy (TEM) has been used to determine the microstructure of the implanted sample. A 6H-SiC wafer was implanted at a temperature of 1800 °C with 40 keV Al ions to a dose of 2 x 1016 cm-2. It was established that an Al step-like profile starts at the interface between the crystal region and the damaged layer. The radiation enhanced diffusion coefficient of Al at the interface was determined to be Di = 2.8 x 10-12 cm2/s, about two orders of magnitude higher than the thermally activated diffusion coefficient. The Si vacancy-rich near-surface layer formed by this implantation condition is believed to play a significant role in enhanced Al diffusion.

Mechanism of Enhanced Diffusion of Aluminum in 6H-SiC in the Process of High-Temperature Ion Implantation

1997 ◽  
Vol 504 ◽  
Author(s):  
Igor O. Usov ◽  
A. A. Suvorova ◽  
V. V. Sokolov ◽  
Y. A. Kudryavtsev ◽  
A. V. Suvorov
Keyword(s):  
Mass Spectrometry ◽  
Diffusion Coefficient ◽  
High Temperature ◽  
Ion Implantation ◽  
Room Temperature ◽  
Secondary Ion Mass Spectrometry ◽  
Diffusion Mechanism ◽  
Enhanced Diffusion ◽  
Sic Wafer ◽  
Secondary Ion

ABSTRACTThe diffusion of Al in 6H-SiC during high-temperature ion implantation was studied using secondary ion mass spectrometry. A 6H-SiC wafer was implanted with 50 keV Al ions to a dose of 1.4E16 cm−2 in the high temperature range 1300°–1800TC and at room temperature. There are two diffusion regions that can be identified in the Al profiles. At high Al concentrations the gettering related peak and profile broadening are observed. At low Al concentrations, the profiles have a sharp kink and deep penetrating diffusion tails. In the first region, the diffusion coefficient is temperature independent, while in the second it exponentially increases as a function of temperature. The Al redistribution can be explained with the substitutional-interstitial diffusion mechanism.

Mechanisms and Kinetics of Iion Beam-Induced Compositional Modifications

1988 ◽  
Vol 100 ◽  
Author(s):  
N. Q. Lam
Keyword(s):  
Synergistic Effects ◽  
Relative Significance ◽  
Near Surface ◽  
Enhanced Diffusion ◽  
Thermally Activated ◽  
Target Composition ◽  
Radiation Enhanced Diffusion ◽  
Radiation Induced ◽  
The Individual ◽  
Kinetics Of

ABSTRACTNear-surface compositional modification of ion-bombarded alloys results from the dynamic interplay of several atomistic processes. In addition to displacement mixing leading to t randomization of atomic locations, which is dominant at relatively low temperatures, and preferential loss of alloying elements by sputtering, many thermally-activated processes, including radiation-enhanced diffusion, radiation-induced segregation and Gibbsian adsorption, also play important roles. The relative contributions of these processes to the evolution of the target composition profile depends on the target materials and irradiation variables. Although a good understanding of the individual processes has been achieved, information regarding their synergistic effects on alloy surface modification is still limited. In the present article, these processes will be characterized in simple physical terms, and the present understanding of their relative significance and contributions in changing the target composition during ion bombardment will be discussed in view of recent progress in theoretical modeling and experimental study.

Effects of Concurrent Co or Ti Silicidation on Transient Diffusion and End-of-Range Damage in Phosphorus Implanted Silicon

1992 ◽  
Vol 262 ◽  
Author(s):  
J.W. Honeycutt ◽  
J. Ravi ◽  
G. A. Rozgonyi
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Complete Removal ◽  
Dislocation Loops ◽  
Enhanced Diffusion ◽  
Depth Profiles ◽  
Enhanced Dissolution ◽  
Implantation Damage ◽  
Transmission Electron ◽  
Defect Behavior ◽  
Secondary Ion

ABSTRACTThe effects of Ti and Co silicidation on P+ ion implantation damage in Si have been investigated. After silicidation of unannealed 40 keV, 2×1015 cm-2 P+ implanted junctions by rapid thermal annealing at 900°C for 10–300 seconds, secondary ion mass spectrometry depth profiles of phosphorus in suicided and non-silicided junctions were compared. While non-silicided and TiSi2 suicided junctions exhibited equal amounts of transient enhanced diffusion behavior, the junction depths under COSi2 were significantly shallower. End-of-range interstitial dislocation loops in the same suicided and non-silicided junctions were studied by planview transmission electron microscopy. The loops were found to be stable after 900°C, 5 minute annealing in non-silicided material, and their formation was only slightly effected by TiSi2 or COSi2 silicidation. However, enhanced dissolution of the loops was observed under both TiSi2 and COSi2, with essentially complete removal of the defects under COSi2 after 5 minutes at 900°C. The observed diffusion and defect behavior strongly suggest that implantation damage induced excess interstitial concentrations are significantly reduced by the formation and presence of COSi2, and to a lesser extent by TiSi2. The observed time-dependent defect removal under the suicide films suggests that vacancy injection and/or interstitial absorption by the suicide film continues long after the suicide chemical reaction is complete.

Motion of Crystal/Crystal and Crystal/Amorphous Interfaces

1990 ◽  
Vol 183 ◽  
Author(s):  
J. L. Batstone
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Temperature ◽  
Grain Boundary ◽  
Boundary Motion ◽  
High Temperature Annealing ◽  
Thermally Activated ◽  
Transmission Electron ◽  
Grain Boundary Motion

AbstractMotion of ordered twin/matrix interfaces in films of silicon on sapphire occurs during high temperature annealing. This process is shown to be thermally activated and is analogous to grain boundary motion. Motion of amorphous/crystalline interfaces occurs during recrystallization of CoSi2 and NiSi2 from the amorphous phase. In-situ transmission electron microscopy has revealed details of the growth kinetics and interfacial roughness.

Attritious Wear of Silicon Carbide

1976 ◽  
Vol 98 (4) ◽  
pp. 1125-1134 ◽  
Author(s):  
R. Komanduri ◽  
M. C. Shaw
Keyword(s):  
Silicon Carbide ◽  
Electron Microscope ◽  
High Temperature ◽  
High Speed ◽  
Layer By Layer ◽  
Wear Area ◽  
Work Material ◽  
Transmission Electron ◽  
Metal Silicides ◽  
Boundary Fracture

Attritious wear of silicon carbide in simulated grinding tests against a cobalt base superalloy at high speed and extremely small feed rate was studied using a scanning electron microscope (SEM) and an auger electron spectroscope (AES). In many cases the wear area of silicon carbide was found to be concave rather than planar in shape. Several microcracks and grain boundary fracture were also observed. No evidence of metal build-up was observed on silicon carbide which was not the case with aluminum oxide. AES study of the rubbed surface on the work material and transmission electron microscope (TEM) investigation of the wear debris suggest that attritious wear of silicon carbide is due to one or more of the following mechanisms: 1 – Preferential removal of surface atoms on the abrasive, layer by layer, by oxidation under high temperature and a favorably directed shear stress; 2 – disassociation of silicon carbide at high temperature and (a) diffusion of silicon into the work material and formation of metal silicides and (b) diffusion of carbon into the work material and formation of unstable metal carbides (in the present case Ni3C and Co3C) which decompose during cooling to metal and carbon atoms; 3 – pinocoidal cleavage fracture of silicon carbide on basal planes c(0001) resulting in the removal of many micron-sized crystallites.

scholarly journals High-Temperature Reliability of GaN Electronic Devices

2000 ◽  
Vol 5 (S1) ◽  
pp. 369-375 ◽  
Author(s):  
Seikoh Yoshida ◽  
Joe Suzuki
Keyword(s):  
High Temperature ◽  
Electrode Materials ◽  
Secondary Ion Mass Spectrometry ◽  
Current Injection ◽  
Current Gain ◽  
Semiconductor Interface ◽  
Gas Source ◽  
Transmission Electron ◽  
Continuous Current ◽  
Junction Transistor

High-quality GaN was grown using gas-source molecular-beam epitaxy (GSMBE). The mobility of undoped GaN was 350 cm2/Vsec and the carrier concentration was 6×1016 cm−3 at room temperature. A GaN metal semiconductor field-effect transistor (MESFET) and an n-p-n GaN bipolar junction transistor (BJT) were fabricated for high-temperature operation. The high-temperature reliability of the GaN MESFET was also investigated. That is, the lifetime of the FET at 673 K was examined by continuous current injection at 673 K. We confirmed that the FET performance did not change at 673 K for over 1010 h. The aging performance of the BJT at 573 K was examined during continuous current injection at 573 K for over 850 h. The BJT performance did not change at 573 K. The current gain was about 10. No degradation of the metal-semiconductor interface was observed by secondary ion-mass spectrometry (SIMS) and transmission electron microscopy (TEM). It was also confirmed by using Si-ion implantation that the contact resistivity of the GaN surface and electrode materials could be lowered to 7×10−6 ohmcm2.

From the Mystery to the Understanding of the Self-Interstitials in Silicon

1980 ◽  
Vol 2 ◽  
Author(s):  
W. Frank ◽  
A. Seeger ◽  
U. Gösele
Keyword(s):  
High Temperature ◽  
The Self ◽  
Experimental Conditions ◽  
Group V ◽  
Group Iii ◽  
Enhanced Diffusion ◽  
Self Diffusion ◽  
Thermally Activated ◽  
Temperature Equilibrium ◽  
K Concentration

ABSTRACTOur present knowledge on self-interstitials in silicon and the rôle these defects play under widely different experimental conditions are surveyed. In particular, the following phenomena involving self-interstitials either in supersaturations or under high-temperature thermal-equilibrium conditions are considered: mobility-enhanced diffusion of self-interstitials below liquid-helium temperature, thermally activated diffusion of self-interstitials at inter-mediate temperatures (14O K to 600 K), concentration-enhanced diffusion of Group-III or Group-V elements in silicon at higher temperatures, and— as examples for high-temperature equilibrium phenomena — self-diffusion and diffusion of gold in silicon. This leads to the picture that the self-interstitials in silicon may occur in different electrical charge states and possess dumbbell configurations or are extended over several atomic volumes at intermediate or high temperatures, respectively.

Ni/Si-Based Contacts to GaN: Thermally Activated Structural Transformations Leading to Ohmic Behavior

1998 ◽  
Vol 537 ◽  
Author(s):  
E. Kaminska ◽  
A. Piotrowska ◽  
J. Jasinski ◽  
J. Kozubowski ◽  
A. Barcz ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Secondary Ion Mass Spectrometry ◽  
Structural Transformations ◽  
Thermally Activated ◽  
Ohmic Behavior ◽  
Transmission Electron ◽  
Dopant Atoms ◽  
Ohmic Contact Formation ◽  
Secondary Ion

AbstractStructural transformations in Ni/Si-based contacts to GaN occurring under heat treatment have been studied using transmission electron microscopy and secondary ion mass spectrometry. Transition from non-ohmic to ohmic behavior correlates with reaction between Ni and Si, and decomposition of the initially formed interfacial Ni:Ga:N layer. Transport of dopant atoms from metallization into GaN testifies in favour of the SPR process of ohmic contact formation

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