High temperature HVPE of AlN on sapphire templates

Baker, Troy J.; Mayo, Ashley; Veisi, Zeinab; Lü, Peng; Schmitt, Jason

doi:10.1002/pssc.201300496

Cited by 16 publications

(7 citation statements)

References 6 publications

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“…The change of geometric characteristics for macrosteps results in different TDD values. Among all the samples, sample A has the highest TDD value of 7.0 × 10 9 cm –2 , which is close to the average TDD value achieved by the TSG technique. ,− In sharp contrast, the TDD value of sample H is decreased to 1.4 × 10 9 cm –2 , only 20% of the average TDD value. The TDD and thickness values of AlN/sapphire templates achieved by the TSG technique reported in the past few years are shown in Figure for comparison.…”

Section: Resultsmentioning

confidence: 99%

Low-Defect-Density Aluminum Nitride (AlN) Thin Films Realized by Zigzag Macrostep-Induced Dislocation Redirection

Jia

et al. 2021

Crystal Growth & Design

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Owing to the lack of large-diameter and affordable AlN bulk crystals, high-quality AlN films grown on sapphire substrates have been intensively analyzed for the potential applications in optoelectronic and electronic devices. Herein, we successfully fabricated low-defect-density AlN thin films on large-offcut-angle sapphire substrates combining magnetron sputtering and metal–organic chemical vapor deposition. It is found that the crystalline qualities of AlN films strongly depend on the densities and geometric features of atomic steps. When high-density zigzag macrosteps are formed on the surface, they can induce dislocation inclination toward multiple directions rather than a single one. In this situation, the inclined dislocations can interact with not only vertical dislocations but also other inclined dislocations. Profiting from the large inclination angles (30–78°), the lateral interaction range of dislocations exhibits a 6-fold increase at most, leading to more frequent dislocation interactions within a relatively thin layer. As a result, the threading dislocation density value of 1 μm thick AlN is reduced down to 1.4 × 109 cm–2, demonstrating an 80% decrease in comparison with its counterpart without the macrostep-induced dislocation redirection effect. This approach is expected to boost the development of low-cost and high-performance devices on AlN/sapphire templates.

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Section: Resultsmentioning

confidence: 99%

Low-Defect-Density Aluminum Nitride (AlN) Thin Films Realized by Zigzag Macrostep-Induced Dislocation Redirection

Jia

et al. 2021

Crystal Growth & Design

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“…These data allow the determination of mean values of residual stress. For all reactor designs and all optimized conditions by the authors [18][19][20][21][22][23][24][25][26][27][28], FWHM values were in the range of 100 to 600 arcsec and 500 to 800 arcsec for on-axis and off-axis peak, respectively. It is clear that the optimal temperature range is 1200-1400 • C to increase the Al mobility on the surface while avoiding sapphire degradation and/or etching [38].…”

Section: Introductionmentioning

confidence: 96%

“…In most recent papers [17][18][19][20][21][22][23][24][25][26][27][28] dealing with HVPE growth of AlN at high temperature from chlorinated precursors, intense efforts have been made to reduce defect densities caused by stress [29][30][31] before optimizing optical properties [18]. In situ etching to control void formation and stress release [17], multi-step methods to control island coalescence [32][33][34] or N/Al ratio [33,35], pulse injection of precursors [36], substrate position in turbulent flow [37] have been proposed to reduce strain, high dislocation densities and the appearance of cracks.…”

Section: Introductionmentioning

confidence: 99%

Epitaxial Growth of AlN on (0001) Sapphire: Assessment of HVPE Process by a Design of Experiments Approach

et al. 2017

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Abstract:This study aims to present the interest of using a design of experiments (DOE) approach for assessing, understanding and improving the hydride vapor phase epitaxy (HVPE) process, a particular class of chemical vapor deposition (CVD) process. The case of the HVPE epitaxial growth of AlN on (0001) sapphire will illustrate this approach. The study proposes the assessment of the influence of 15 process parameters on the quality or desired properties of the grown layers measured by 9 responses. The general method used is a screening design with the Hadamard matrix of order 16. For the first time in the growth of AlN by CVD, a reliable estimation of errors is proposed on the measured responses. This study demonstrates that uncontrolled release of condensed species from the cold wall is the main drawback of this process, explaining many properties of the grown layers that could be mistakenly attributed to other phenomena without the use of a DOE. It appears also that the size of nucleation islands, and its corollary, the stress state of the layer at room temperature, are key points. They are strongly correlated to the crystal quality. Due to the intrinsic limitations of the screening design, the complete optimization of responses cannot be proposed but general guidelines for hydride (or halogen) vapor phase epitaxy (HVPE) experimentations, in particular with cold wall apparatus, are given.

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“…Molecular rings and cage-compounds with an Al-N skeleton have been extensively studied in view of their structural diversity and the application to obtain the semi-conductor AlN. [1][2][3][4][5][6][7][8][9] If an alane X 3 Al is allowed to react with an amine NY 3 , the chemical nature and partial charge of the substituent plays the key role for the formation of the final product. This can be a simple adduct by Lewis acid-base interaction of the starting materials (X 3 Al-NY 3 ) or after elimination of X-Y may lead to connected Al-N entities, which differ in their three-dimensional alignment.…”

Section: Introductionmentioning

confidence: 99%

“…Molecular rings and cage‐compounds with an Al‐N skeleton have been extensively studied in view of their structural diversity and the application to obtain the semi‐conductor AlN . If an alane X 3 Al is allowed to react with an amine N Y 3 , the chemical nature and partial charge of the substituent plays the key role for the formation of the final product.…”

Section: Introductionmentioning

confidence: 99%

Aluminum/Nitrogen Cycles and an Open Cage with Al–H and N–H Functions

Veith

Walgenbach

Hüch

et al. 2017

Zeitschrift anorg allge chemie

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The cyclic tert‐butyl‐amino alane dimer [tBu–N(H)AlH2]2 (1) was obtained from reaction between alane with tert‐butylamine and its boranate derivative [tBu–N(H)–Al(BH4)2)]2 (2) subsequently from 1 by hydride/chloride exchange using PbCl2 followed by reaction with LiBH4. Both compounds form four‐membered Al2N2 cycles with typical Al–N bond lengths of 1.940(5) Å (1) and 1.945(5) Å (2) as found from X‐ray diffraction analysis. The tert‐butyl substituents at the nitrogen atoms may be situated at the same side of the ring (cis) or at opposite sides (trans). For compound 1 both isomers are present in solution, showing particular temperature dependent NMR shifts. In the solid both compounds 1 and 2 adopt the trans arrangement. When 1 is reacted with PbCl2 in half of the molarity ratio used for 2, surprisingly the novel compound 3, a zwitterion, can be obtained: [(tBu–N)(Al–H)3(tBu–N(H))3Cl((H)N–tBu)3(Al–H)2(Al–Cl)(N–tBu)]+[(tBu–N)(tBu–N(H))(AlCl2)2]–. X‐ray structure analysis reveals that the anion is made of a tert‐butyl amino aluminum dichloride dimer (central Al2N2 ring) with one of the two nitrogen atoms being deprotonated. The cationic counterpart consists of three entities: (i) There is a first seco‐norcubane like Al3N4 basket with tert‐butyl groups at the nitrogen atoms, two hydride and one chloride ligand at the aluminum atoms and three hydrogen atoms on the open side of the basket, all pointing in the same direction; (ii) There is a second similar Al3N4 basket with the same substituent pattern except that all aluminum atoms have exclusively hydrogen ligands; (iii) Both baskets coordinate a central chloride through the six protons at the open nitrogen face of the baskets in such a way that the chloride lies in the center of a H6 trigonal anti‐prism [mean H–Cl–H = 56.1(9)°]. As each of the open cages has a positive charge the overall charge by combination with the chloride adds to +1. The structure of the cationic part of 3 is unprecedented in AlN polycycles.

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High temperature HVPE of AlN on sapphire templates

Cited by 16 publications

References 6 publications

Low-Defect-Density Aluminum Nitride (AlN) Thin Films Realized by Zigzag Macrostep-Induced Dislocation Redirection

Low-Defect-Density Aluminum Nitride (AlN) Thin Films Realized by Zigzag Macrostep-Induced Dislocation Redirection

Epitaxial Growth of AlN on (0001) Sapphire: Assessment of HVPE Process by a Design of Experiments Approach

Aluminum/Nitrogen Cycles and an Open Cage with Al–H and N–H Functions

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