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Structural Characterization of Iii-Nitride Semiconductors: Defect Control and Strain Management.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Structural Characterization of Iii-Nitride Semiconductors: Defect Control and Strain Management./
Author:	Guan, Yan.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2022,
Description:	154 p.
Notes:	Source: Dissertations Abstracts International, Volume: 84-01, Section: B.
Contained By:	Dissertations Abstracts International84-01B.
Subject:	Crystal structure. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29176834
ISBN:	9798835546992

Structural Characterization of Iii-Nitride Semiconductors: Defect Control and Strain Management.
Guan, Yan.

Structural Characterization of Iii-Nitride Semiconductors: Defect Control and Strain Management. - Ann Arbor : ProQuest Dissertations & Theses, 2022 - 154 p.

Source: Dissertations Abstracts International, Volume: 84-01, Section: B.

Thesis (Ph.D.)--North Carolina State University, 2022.

This item must not be sold to any third party vendors.

GUAN, YAN. Structural Characterization of III-Nitride Semiconductors: Defect Control and Strain Management. (Under the direction of Dr. Zlatko Sitar and Dr. Ramon Collazo).Defects in III-nitride films and their influence on optical, electrical, and mechanical properties were investigated. Defects reduction by thermal treatments and strain management via epitaxy growth modulation were realized. High-resolution x-ray diffraction was used to provide rapid and accurate information on defect characterization and composition and strain determination and proved as an ideal characterization tool in III-nitride semiconductors. Damage recovery was demonstrated in Si implanted AlN and Mg implanted GaN by low temperature annealing (T ≤ 600 °C). A fast damage recovery was initiated at an unexpected low annealing temperature of 160 °C, then followed by a slow recovery with further increasing annealing temperature beyond 350 °C. The recovery kinetics was studied by means of isothermal and isochronal anneals. The activation energies were estimated as 1.9±0.3 eV and 1.7±0.1 eV for Si implanted AlN and Mg implanted GaN respectively. The strain recovery by low temperature annealing was attributed to the fast recombination of vacancies and interstitials of the matrix atoms. Multicyles of properly designed implantion along with low temperature annealing are suggested for complete lattice damage recovery and electrical activation.High crystalline quality AlN and Al-rich AlGaN on sapphire were obtained by high temperature annealing. AlN capping layer was utilized a robust diffusion barrier to suppress Ga related decomposition during high temperature annealing. The kinetics of dislocation reduction was investigated as a function of annealing temperature and time. Dislocation climb through vacancy core diffusion was identified as the dominant recovery mechanism. The activation energy for dislocation recovery in AlN was estimated as 4.3 ± 0.1 eV. The utilization of thin AlGaN layers in this method prohibited the appearance of severe wafer bowing. The influence of chemical potentials on strain development in Si-doped Al-rich AlGaN on sapphire was investigated. NH3 flow rate was employed as the experimental variable to affect the chemical potentials of N. Tensile stress introduced by dislocation climbing increased with NH3 flow rates under identical Si concentrations, indicating that the complexes rather than Si dopant per se affect the stress evolution. The chemical potential control model is suggested for strain management in III-nitrides via systematically modulating the MOCVD growth conditions to increase the formation energy of vacancies or vacancy complexes. Strain relaxation mechanism was investigated in Ga-rich AlGaN on AlN single crystal substrates. Asymmetric reciprocal space mapping manifested almost full relaxation in 1 µm thick Al0.25Ga0.75N on AlN substrate. Without preexisting dislocations from native substrates, strain relaxation occurred via the generation of new dislocations. Three types of dislocations were directly observed by TEM: the long, straight misfit dislocations along the directions, substantial curved dislocation tangles on basal planes, and threading dislocations stemming from them. The formation of curved dislocation tangles on basal planes was determined as the dominant strain relaxation mechanism.

ISBN: 9798835546992Subjects--Topical Terms:

3561040
Crystal structure.

Structural Characterization of Iii-Nitride Semiconductors: Defect Control and Strain Management.
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260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2022
300 $a 154 p.
500 $a Source: Dissertations Abstracts International, Volume: 84-01, Section: B.
500 $a Advisor: Lunardi, Leda;Gao, Wenpei.
502 $a Thesis (Ph.D.)--North Carolina State University, 2022.
506 $a This item must not be sold to any third party vendors.
520 $a GUAN, YAN. Structural Characterization of III-Nitride Semiconductors: Defect Control and Strain Management. (Under the direction of Dr. Zlatko Sitar and Dr. Ramon Collazo).Defects in III-nitride films and their influence on optical, electrical, and mechanical properties were investigated. Defects reduction by thermal treatments and strain management via epitaxy growth modulation were realized. High-resolution x-ray diffraction was used to provide rapid and accurate information on defect characterization and composition and strain determination and proved as an ideal characterization tool in III-nitride semiconductors. Damage recovery was demonstrated in Si implanted AlN and Mg implanted GaN by low temperature annealing (T ≤ 600 °C). A fast damage recovery was initiated at an unexpected low annealing temperature of 160 °C, then followed by a slow recovery with further increasing annealing temperature beyond 350 °C. The recovery kinetics was studied by means of isothermal and isochronal anneals. The activation energies were estimated as 1.9±0.3 eV and 1.7±0.1 eV for Si implanted AlN and Mg implanted GaN respectively. The strain recovery by low temperature annealing was attributed to the fast recombination of vacancies and interstitials of the matrix atoms. Multicyles of properly designed implantion along with low temperature annealing are suggested for complete lattice damage recovery and electrical activation.High crystalline quality AlN and Al-rich AlGaN on sapphire were obtained by high temperature annealing. AlN capping layer was utilized a robust diffusion barrier to suppress Ga related decomposition during high temperature annealing. The kinetics of dislocation reduction was investigated as a function of annealing temperature and time. Dislocation climb through vacancy core diffusion was identified as the dominant recovery mechanism. The activation energy for dislocation recovery in AlN was estimated as 4.3 ± 0.1 eV. The utilization of thin AlGaN layers in this method prohibited the appearance of severe wafer bowing. The influence of chemical potentials on strain development in Si-doped Al-rich AlGaN on sapphire was investigated. NH3 flow rate was employed as the experimental variable to affect the chemical potentials of N. Tensile stress introduced by dislocation climbing increased with NH3 flow rates under identical Si concentrations, indicating that the complexes rather than Si dopant per se affect the stress evolution. The chemical potential control model is suggested for strain management in III-nitrides via systematically modulating the MOCVD growth conditions to increase the formation energy of vacancies or vacancy complexes. Strain relaxation mechanism was investigated in Ga-rich AlGaN on AlN single crystal substrates. Asymmetric reciprocal space mapping manifested almost full relaxation in 1 µm thick Al0.25Ga0.75N on AlN substrate. Without preexisting dislocations from native substrates, strain relaxation occurred via the generation of new dislocations. Three types of dislocations were directly observed by TEM: the long, straight misfit dislocations along the directions, substantial curved dislocation tangles on basal planes, and threading dislocations stemming from them. The formation of curved dislocation tangles on basal planes was determined as the dominant strain relaxation mechanism.
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