Effect of Substrate Surface Defects and Te Dopant Concentration on Crystalline Quality and Electrical Characteristics of AlGaAsSb Epitaxial Layers
Abstract
The influence of GaSb substrate surface defects such as native oxides on the crystalline quality of epitaxial layers was investigated using transmission electron microscopy (TEM). Cross sectional TEM imaging showed that there are discrete defects at the GaSb-substrate/epilayer interface. Secondary ion mass spectroscopy (SIMS) results revealed high oxygen concentration at the interface, indicating that the defects are likely oxides and presumed to be native oxides since other impurities were not detected. High resolution TEM micrographs showed that the subsequent growth of the epilayer continues beyond the defects without any additional defect generation or propagation. Tellurium doped AlGaAsSb epitaxial layers were grown lattice-matched on GaSb substrates and lattice-mismatched on semi-insulating GaAs substrates by organometallic vapor phase epitaxy. Secondary ion mass spectroscopy and Hall data showed that the ratio of carrier concentration to Te concentration decreases significantly when the carrier concentration increases from 2.5 x 10{sup 17} cm{sup -3} to 6.5 x 10{sup 17} cm{sup -3}. TEM imaging showed that the material with heavily doped Te generates a high density (about 10{sup 8} cm{sup 2}) of planar defects (stacking fault) located on (111) planes. Most of the Te-related defects originate at the GaSb buffer layer/AlGaAsSb epilayer interface. In addition, discrete precipitates weremore »
- Authors:
- Publication Date:
- Research Org.:
- Knolls Atomic Power Laboratory (KAPL), Niskayuna, NY
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 875457
- Report Number(s):
- LM-05K176
TRN: US200605%%22
- DOE Contract Number:
- DE-AC12-00SN39357
- Resource Type:
- Conference
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 42 ENGINEERING; BUFFERS; DEFECTS; IMPURITIES; MASS SPECTROSCOPY; OXIDES; OXYGEN; RESOLUTION; SUBSTRATES; TELLURIUM; TRANSMISSION ELECTRON MICROSCOPY; VAPOR PHASE EPITAXY
Citation Formats
H Ehsani, N Lewis, G Nichols, L Danielson, M Dashiell, Z Shellenbarger, and C Wang. Effect of Substrate Surface Defects and Te Dopant Concentration on Crystalline Quality and Electrical Characteristics of AlGaAsSb Epitaxial Layers. United States: N. p., 2006.
Web.
H Ehsani, N Lewis, G Nichols, L Danielson, M Dashiell, Z Shellenbarger, & C Wang. Effect of Substrate Surface Defects and Te Dopant Concentration on Crystalline Quality and Electrical Characteristics of AlGaAsSb Epitaxial Layers. United States.
H Ehsani, N Lewis, G Nichols, L Danielson, M Dashiell, Z Shellenbarger, and C Wang. Wed .
"Effect of Substrate Surface Defects and Te Dopant Concentration on Crystalline Quality and Electrical Characteristics of AlGaAsSb Epitaxial Layers". United States.
doi:. https://www.osti.gov/servlets/purl/875457.
@article{osti_875457,
title = {Effect of Substrate Surface Defects and Te Dopant Concentration on Crystalline Quality and Electrical Characteristics of AlGaAsSb Epitaxial Layers},
author = {H Ehsani and N Lewis and G Nichols and L Danielson and M Dashiell and Z Shellenbarger and C Wang},
abstractNote = {The influence of GaSb substrate surface defects such as native oxides on the crystalline quality of epitaxial layers was investigated using transmission electron microscopy (TEM). Cross sectional TEM imaging showed that there are discrete defects at the GaSb-substrate/epilayer interface. Secondary ion mass spectroscopy (SIMS) results revealed high oxygen concentration at the interface, indicating that the defects are likely oxides and presumed to be native oxides since other impurities were not detected. High resolution TEM micrographs showed that the subsequent growth of the epilayer continues beyond the defects without any additional defect generation or propagation. Tellurium doped AlGaAsSb epitaxial layers were grown lattice-matched on GaSb substrates and lattice-mismatched on semi-insulating GaAs substrates by organometallic vapor phase epitaxy. Secondary ion mass spectroscopy and Hall data showed that the ratio of carrier concentration to Te concentration decreases significantly when the carrier concentration increases from 2.5 x 10{sup 17} cm{sup -3} to 6.5 x 10{sup 17} cm{sup -3}. TEM imaging showed that the material with heavily doped Te generates a high density (about 10{sup 8} cm{sup 2}) of planar defects (stacking fault) located on (111) planes. Most of the Te-related defects originate at the GaSb buffer layer/AlGaAsSb epilayer interface. In addition, discrete precipitates were observed in the heavily doped AlGaAsSb layer.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 04 00:00:00 EST 2006},
month = {Wed Jan 04 00:00:00 EST 2006}
}
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Tellurium doped AlGaAsSb epitaxial layers were grown lattice-matched on GaSb substrates and lattice-mismatched on semi-insulating GaAs substrates by organometallic vapor phase epitaxy. Secondary ion mass spectroscopy and Hall data showed that the ratio of carrier concentration to Te concentration decreases from 40% to 5% when the Te concentration increases from 4.8 x 10{sup 17} cm{sup -3} to 1.3 x 10{sup 19} cm{sup -3}. Transmission electron microscopy (TEM) showed that the material with heavily doped Te generates a high density (about 10{sup 8} cm{sup 2}) of planar defects. Most of the Te-related defects originate at the GaSb buffer layer/AlGaAsSb epilayer interface.more »
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Heavily Si-doped, strain-relaxed In{sub 0.5}Ga{sub 0.5}As layers are often used as contact layers on N{sup +}GaAs to form nonalloyed ohmic contacts. The present work studies the electrical properties of such In{sub 0.5}Ga{sup 0.5}As layers grown on undoped GaAs buffer layers by molecular beam epitaxy both as-grown and after anneals at temperatures between 300 and 430 {degrees}C. It is found that in the as-grown condition, there is a region of about 150 {Angstrom} extending into the In{sub 0.5}Ga{sub 0.5}As layer contiguous to the In{sub 0.5}Ga{sub 0.5}As/GaAs interface where both the electron concentration and mobility decrease toward the interface. With postgrowth anneal,more » -
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We have grown Nb-doped TiO{sub 2} epitaxial films on (100) and (110)-oriented TiO{sub 2} rutile substrates by molecular beam epitaxy. Nb substitutionally incorporates at cation sites in the rutile lattice, forming Nb{sub {ital x}}Ti{sub 1{minus}{ital x}}O{sub 2} solid solutions. However, the crystal quality and surface roughness of the films depend strongly on the substrate orientation. Surface roughening and defect formation occur at lower values of {ital x} on (100) than on (110). This result is due to anisotropic changes in the metal-oxygen bond lengths within the rutile structure in going from TiO{sub 2} to NbO{sub 2}; there are 1{percent} andmore » -
Surface damages in diamond by Ar/O{sub 2} plasma and their effect on the electrical and electrochemical characteristics of boron-doped layers
Epitaxial single crystal and boron-doped diamond layers were exposed to reactive ion etching in Ar/O{sub 2} plasma (rf power of 25 W and self-bias of 100 V); and the electrical, structural, and electrochemical characteristics of the exposed surface were investigated. Angle-resolved x-ray photoemission spectroscopy (XPS) measurements revealed a nonuniform layer of amorphous carbon at the exposed surface with an average thickness of approximately 4 nm, as confirmed also by atomic force microscopy profiling of selectively etched areas. On highly boron-doped diamond, the plasma-induced damages resulted also in a nonconductive surface layer. This damaged and insulating surface layer remained resistant tomore »