Large area GaN substrates

Kryliouk, O.; Reed, M. D.; Dann, Todd; Anderson, Tim; Chai, B. H. T.

doi:10.1016/s0921-5107(99)00114-2

Cited by 32 publications

(17 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The sulphides and selenides crystallising in the orthorhombic β-NaFeO 2 structure [16][17][18][19] have been found to be promising materials for practical application in nonlinear optical devices [19][20][21]. LiGaO 2 crystallising also in the β-NaFeO 2 structure [19,22] originally considered as a promising refractory piezoelectric transducer material [23] has now attracted attention for ____________________ application as substrate for the growth of thick single crystalline GaN layers [24] and as a candidate for the realisation of devices based on field effect carrier modulation or superlattices in combination with ZnO [25]. LiInO 2 which is known to crystallise in the tetragonal α-LiFeO 2 structure [26] is one of the materials considered as a solid-state scintillator for solar neutrinos [27].…”

Section: Introductionmentioning

confidence: 99%

Lattice dynamics and related properties of A^IB^III and A^IIB^IV compounds, I. Elastic constants

Neumann¹

2004

Cryst. Res. Technol.

View full text Add to dashboard Cite

The present state of knowledge of the elastic properties of the ternary chalcopyrite compounds and some related materials is reviewed. Results of experimental elastic constant determinations are critically evaluated by comparing with other experimentally available material parameters that directly depend on the elastic constants. Possible reasons for existing discrepancies and obvious inconsistencies in the experimental data are discussed. The results of theoretical calculations of the elastic constants of these compounds based on different theoretical models and approaches are compared with experimental data and are assessed concerning achievable accuracy and reliability.

show abstract

Section: Introductionmentioning

confidence: 99%

Lattice dynamics and related properties of A^IB^III and A^IIB^IV compounds, I. Elastic constants

Neumann¹

2004

Cryst. Res. Technol.

View full text Add to dashboard Cite

show abstract

“…[18][19][20][21] However, in order to efficiently use this method and in a controlled way reduce the density of dislocations a good understanding of the mechanism responsible for such reduction is needed. There are only a few papers in the literature, which discus the dislocation reduction process in thick HVPE GaN layers and their conclusions seemed to be somewhat contradictory.…”

Section: Introductionmentioning

confidence: 99%

Extended defects and polarity of hydride vapor phase epitaxy GaN

Jasiński

Liliental‐Weber

2002

Journal of Elec Materi

View full text Add to dashboard Cite

Hydride vapor phase epitaxy (HVPE) GaN layers on sapphire substrates and so-called free-standing platelets (layers removed from the sapphire)were studied by different transmission electron microscopy (TEM) techniques. Polarity determined by convergent beam electron diffraction (CBED) and distribution of structural defects, determined by conventional TEM, are discussed. HVPE layers were found to grow primarily with Gapolarity. A few inversion domains (areas with N-polarity) were observed on the substrate side of one of the free-standing layers. The dominant structural defects in HVPE GaN layers are threading dislocations. A systematic reduction of their density with increase in layer thickness was observed for all samples. The experimental results indicate that the density of dislocations is inversely proportional to the distance from the substrate, which agrees with the theoretical model. INTRODUCTIONIn recent years, GaN-based semiconductors have attracted scientific interest because of their importance in many applications, mostly in optoelectronic, and highpower, and high-temperature electronic devices. Good quality GaN-based light-emitting diodes, blue lasers and metal-semiconductor field-effect transistors have been demonstrated. [1][2][3][4][5][6] Despite the large number of applications and wide spread interest in GaN and other III-nitrides there are still some problems associated with the technology of these materials. One of them is the problem with available substrates for epitaxial growth of nitride semiconductor layers. There are still some difficulties in growing large bulk Advanced Institute of Technology. The last two samples (they will be referred to later in this paper as samples: FS1 and FS2) were also grown on a sapphire substrate and their initial thickness before laser induced lift off 25 was about 300 µm. After separation from the substrate these layers were mechanically polished, and dry etched on their original surface to obtain a smooth epi-ready surface. The opposite surface was only mechanochemically polished. For these two layers TEM plan-view specimens were prepared from both sides and from the remaining ones with the exception of the sample with the thickness of 55 µm where the large accumulated stress caused constant breaking only from the surface side. All TEM specimens were prepared by a standard method of mechanical pre-thinning followed by Ar-ion milling down to electron transparency. TEM 4 studies were carried out using a TOPCON 002B microscope, operated at 200 kV acceleration voltage. RESULTS AND DISCUSSION CRYSTAL POLARITYThe [0001] direction of the GaN layer grown on a c-plane sapphire substrate can have two different polarities. These polarities correspond to orientation of the Ga-N bond, which is parallel to the c-axis. A layer has a Ga-polarity when the growth direction points from the Ga atom towards the N atom. When the growth direction points from the N atom towards the Ga atom a layer has a N-polarity.In order to determine the polarity of the investigated GaN layers ...

show abstract

“…Due to the high N overpressure on GaN and very small solubility of N in a Ga melt, production of large area GaN has not yet been realized. Consequently, the attention has turned to the growth of very thick GaN films 10,11,12,13 on sapphire or other substrates, such as GaAs by HVPE. Due to deposition on sapphire, the large extended defect density is of great concern.…”

Section: Introductionmentioning

confidence: 99%

Characterization of free-standing hydride vapor phase epitaxy GaN

Jasiński

Swider

Liliental‐Weber

et al. 2001

Applied Physics Letters

View full text Add to dashboard Cite

A free-standing GaN template grown to a thickness of 300 µm by hydride vapor phase epitaxy (HVPE) has been characterized for its structural properties by transmission electron microscopy (TEM). The TEM investigation was augmented by X-ray diffraction, defect delineation etching process followed by imaging with atomic force microscopy (AFM), and variable temperature photoluminescence (PL). Convergent Beam Electron Diffraction (CBED) was employed to determine the polarity of the free surface and the side juxtaposed to substrate before separation. The substrates side was confirmed to the N-face indicating a growth in the [0001] direction from Ga to N. The density of dislocations near the N-face was determined to be, in order, 3 ± 1 x 10 7 , 4 ± 1 x 10 7 , and about 1 x 10 7 cm -2 as determined by cross-sectional TEM, plan-view TEM and a defect revealing etch, respectively. Identical observations on the Ga-face revealed the defect concentration to be, in order, less than 1 x 10 7 cm -2 by plan-view TEM, 5 x 10 5 cm -2 by cross-sectional TEM, and 5 x 10 5 cm -2 by defect revealing hot H 3 PO 4 acid, respectively. The full width at half maximum (FWHM) of the symmetric (0002) X-ray diffraction peak was 69 and 160 arcsec for the Ga and N-faces, respectively. That for the asymmetric (1014) peak was 103 and 140 arcsec for Ga-and N-faces, respectively. The donor bound exciton linewidth as measured on the Ga and N-face (after the removal of the damage) is about 1 meV each at 10K. Instead of the commonly observed yellow band, this sample displayed a green band, which is centered at about 2.44 eV.

show abstract

Large area GaN substrates

Cited by 32 publications

References 6 publications

Lattice dynamics and related properties of A^IB^III and A^IIB^IV compounds, I. Elastic constants

Lattice dynamics and related properties of A^IB^III and A^IIB^IV compounds, I. Elastic constants

Extended defects and polarity of hydride vapor phase epitaxy GaN

Characterization of free-standing hydride vapor phase epitaxy GaN

Contact Info

Product

Resources

About

Large area GaN substrates

Cited by 32 publications

References 6 publications

Lattice dynamics and related properties of AIBIII and AIIBIV compounds, I. Elastic constants

Lattice dynamics and related properties of AIBIII and AIIBIV compounds, I. Elastic constants

Extended defects and polarity of hydride vapor phase epitaxy GaN

Characterization of free-standing hydride vapor phase epitaxy GaN

Contact Info

Product

Resources

About

Lattice dynamics and related properties of A^IB^III and A^IIB^IV compounds, I. Elastic constants

Lattice dynamics and related properties of A^IB^III and A^IIB^IV compounds, I. Elastic constants