ВЛИЯНИЕ ТВЕРДОФАЗНОЙ РЕКРИСТАЛЛИЗАЦИИ С ДВОЙНОЙ ИМПЛАНТАЦИЕЙ НА ПЛОТНОСТЬ СТРУКТУРНЫХ ДЕФЕКТОВ В УЛЬТРАТОНКИХ СЛОЯХ КРЕМНИЯ НА САПФИРЕ

2020 ◽  
Vol 96 (3s) ◽  
pp. 154-159
Author(s):  
Н.Н. Егоров ◽  
С.А. Голубков ◽  
С.Д. Федотов ◽  
В.Н. Стаценко ◽  
А.А. Романов ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Solid Phase ◽  
Modern Method ◽  
Structural Defects ◽  
Structural Quality ◽  
Mos Transistors ◽  
Ultrathin Layers ◽  
Heteroepitaxial Layers ◽  
Xrd And Tem

Высокая плотность структурных дефектов является основной проблемой при изготовлении электроники на гетероструктурах «кремний на сапфире» (КНС). Современный метод получения ультратонких структур КНС с помощью твердофазной эпитаксиальной рекристаллизации позволяет значительно снизить дефектность в гетероэпитаксиальном слое КНС. В данной работе ультратонкие (100 нм) слои КНС были получены путем рекристаллизации и утонения субмикронных (300 нм) слоев кремния на сапфире, обладающих различным структурным качеством. Плотность структурных дефектов в слоях КНС оценивалась с помощью рентгеноструктурного анализа и просвечивающей электронной микроскопии. Кривые качания от дифракционного отражения Si(400), полученные в ω-геометрии, продемонстрировали максимальную ширину на полувысоте пика не более 0,19-0,20° для ультратонких слоев КНС толщиной 100 нм. Формирование структурно совершенного субмикронного слоя КНС 300 нм на этапе газофазной эпитаксии обеспечивает существенное уменьшение плотности дислокаций в ультратонком кремнии на сапфире до значений ~1 • 104 см-1. Тестовые n-канальные МОП-транзисторы на ультратонких структурах КНС характеризовались подвижностью носителей в канале 725 см2 Вс-1. The high density of structural defects is the main problem on the way to the production of electronics on silicon-on-sapphire (SOS) heteroepitaxial wafers. The modern method of obtaining ultrathin SOS wafers is solid-phase epitaxial recrystallization which can significantly reduce the density of defects in the SOS heteroepitaxial layers. In the current work, ultrathin (100 nm) SOS layers were obtained by recrystallization and thinning of submicron (300 nm) SOS layers, which have various structural quality. The density of structural defects in the layers was estimated by using XRD and TEM. Full width at half maximum of rocking curves (ω-geometry) was no more than 0.19-0.20° for 100 nm ultra-thin SOS layers. The structural quality of 300 nm submicron SOS layers, which were obtained by CVD, depends on dislocation density in 100 nm ultrathin layers. The dislocation density in ultrathin SOS layers was reduced by ~1 • 104 cm-1 due to the utilization of the submicron SOS with good crystal quality. Test n-channel MOS transistors based on ultra-thin SOS wafers were characterized by electron mobility in the channel 725 cm2 V-1 s-1.

scholarly journals Влияние твердофазной рекристаллизации с двойной имплантацией на плотность структурных дефектов в ультратонких слоях кремния на сапфире

2019 ◽  
Vol 61 (12) ◽  
pp. 2349
Author(s):  
С.Д. Федотов ◽  
В.Н. Стаценко ◽  
Н.Н. Егоров ◽  
С.А. Голубков
Keyword(s):  
Defect Density ◽  
Solid Phase ◽  
Silicon Layer ◽  
Modern Method ◽  
Structural Quality ◽  
Technological Problem ◽  
Recrystallization Process ◽  
Epitaxial Silicon ◽  
Near Surface ◽  
Epitaxial Silicon Layer

The main technological problem in the manufacture of electronics on silicon-on-sapphire (SOS) wafers is the high density of defects in the epitaxial silicon layer. The modern method of obtaining ultrathin SOS wafers using solid-phase epitaxial recrystallization (SPER) and pyrogenic thinning that significantly reduce the defect density in these layers. Nevertheless, the influence of the defect density in submicron SOS layers on the structural quality of ultrathin SOS layers remains unclear. In this work, ultrathin (100 nm) SOS wafers were obtained by SPER of submicron (300 nm) SOS wafers with different structural quality. The crystallinity of 300 nm layers before the recrystallization process and ultrathin layers was determined by XRD and TEM. It was found that the smallest values of the FWHM 0.19-0.20° were observed for the ultrathin SOS layers obtained on the basis of 300 nm SOS wafers with the best structural quality. It was shown that the structural perfect near-surface Si layer, which serves as a seed layer in SPER process, and the double implantation regime allow to reduce the linear defect density in the ultrathin SOS layers by ~ 1×104 cm-1.

The Effect of the Buffer Layer on the Structure, Mobility and Photoluminescence of MBE grown GaN

1999 ◽  
Vol 595 ◽  
Author(s):  
Nikhil Sharma ◽  
David Tricker ◽  
Vicki Keast ◽  
Stewart Hooper ◽  
Jon Heffernan ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Layer Thickness ◽  
Annealing Time ◽  
Defect Density ◽  
Stacking Faults ◽  
Structural Defects ◽  
Structural Quality ◽  
Organic Chemical ◽  
Buffer Layer Thickness

AbstractAlthough GaN has been grown mainly by metal organic chemical vapour deposition (MOCVD), molecular beam epitaxy (MBE) offers the advantages of lower growth temperatures and a more flexible control over doping elements and their concentrations [1]. We are growing GaN by MBE on sapphire substrates, using a GaN buffer layer to reduce the misfit strain, thus improving the structural quality of the epilayer. The quality of the GaN epilayers (in terms of their photoluminescence, mobility and structure) has been investigated as a function of the buffer layer thickness and annealing time.The investigation showed that increasing the buffer layer thickness improved the mobility of the material because the defect density in the GaN epilayer decreased. Optical characterisation showed that the ratio of the donor band exciton (DBE) peak (3.47eV) to the structural peak (3.27eV) in the photoluminescence spectrum, measured at 10K, increased with decreasing defect density. The unwanted structural peak can be considered to originate from a shallow donor to a shallow acceptor transition, which is clearly related to the structural defects in GaN. Thus by increasing the buffer layer thickness and annealing time the structural quality, mobility and photoluminescence improves in the GaN epilayers.Structural characterisation by transmission electron microscopy (TEM) showed that the observed increase in the DBE to structural peak ratio in the photoluminescence spectra could be correlated with a decrease in the density of stacking faults in the GaN epilayers. The detailed structure of these stacking faults was investigated by dark field and high resolution TEM. Their effect on the electrical and optical behaviour of GaN may be assessed by determining the local change in the dielectric function in the vicinity of individual stacking faults.

Characterization of Structural Quality of Bonded Silicon-On-Insulator Wafers by Spectroscopic Ellipsometry and Raman Spectroscopy

2004 ◽  
Vol 809 ◽  
Author(s):  
N. V. Nguyen ◽  
J. E. Maslar ◽  
Jin-Yong Kim ◽  
Jin-Ping Han ◽  
Jin-Won Park ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Dielectric Function ◽  
Spectroscopic Ellipsometry ◽  
Crystalline Silicon ◽  
Silicon On Insulator ◽  
Structural Defects ◽  
Structural Quality ◽  
Ellipsometry Data

ABSTRACTThe crystalline quality of bonded Silicon-On-Insulator (SOI) wafers were examined by spectroscopic ellipsometry and Raman spectroscopy. Both techniques detect slight structural defects in the SOI layer. If a pure crystalline silicon dielectric function is assumed for the SOI layer, the spectroscopic ellipsometry data fitting yields an unacceptably large discrepancy between the experimental and modeled data. The best fits for all the samples result in a dielectric function of the SOI layer that consists of a physical mixture of crystalline silicon and about 4 % to 7 % of amorphous silicon. Using such a mixture indicates that there are still some defects in the SOI layer when compared with the high-quality bulk crystalline silicon. This observation is further supported by Raman spectroscopy measurements. The Raman spectra of all SOI samples exhibit a feature at about 495 cm−1 that is not observed in the crystalline silicon spectrum. Features similar to the 495 cm−1 feature have been reported in the literature and attributed to dislocations or faults in the silicon lattice.

scholarly journals The Role of the Multi Buffer Layer Technique on the Structural Quality of GaN

2000 ◽  
Vol 5 (S1) ◽  
pp. 398-404 ◽  
Author(s):  
M. Benamara ◽  
Z. Liliental-Weber ◽  
J.H. Mazur ◽  
W. Swider ◽  
J. Washburn ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Buffer Layers ◽  
Structural Quality ◽  
Transmission Electron ◽  
Layer Technique ◽  
Growth Method ◽  
Microscopy Techniques ◽  
Edge Dislocations

Successive growth of thick GaN layers separated by either LT-GaN or LT-AlN interlayers have been investigated by transmission electron microscopy techniques. One of the objectives of this growth method was to improve the quality of GaN layers by reducing the dislocation density at the intermediate buffer layers that act as barriers to dislocation propagation. While the use of LT-AlN results in the multiplication of dislocations in the subsequent GaN layers, the LT-GaN reduces dislocation density. Based upon Burgers vector analysis, the efficiency of the buffer layers for the propagation of the different type of dislocations is presented. LT-AlN layer favor the generation of edge dislocations, leading to a highly defective GaN layer. On the other hand, the use of LT-GaN as intermediate buffer layers appears as a promising method to obtain high quality GaN layer.

Structural defects in ZnGeP2single crystals revealed by X-ray topography

2018 ◽  
Vol 51 (4) ◽  
pp. 1043-1049 ◽  
Author(s):  
Zuotao Lei ◽  
Aleksei Kolesnikov ◽  
Anton Vasilenko ◽  
Chongqiang Zhu ◽  
Galina Verozubova ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Dislocation Density ◽  
Chemical Elements ◽  
Structural Defects ◽  
Initial Part ◽  
Large Area ◽  
High Quality ◽  
X Ray ◽  
Vertical Bridgman

The results of X-ray transmission topography and diffraction analysis of a ZnGeP2single crystal grown by the vertical Bridgman method in the [001] direction are presented and discussed. The FWHM of rocking curves over a large area of a (100) longitudinal slice is about 12′′, which is indicative of the high quality of the examined sample. Glow discharge mass spectrometry does not show significant content of foreign chemical elements. X-ray topography reveals growth striations and dislocations. The predominant defects are single dislocations and their pile-ups. Near to the growth-axis region, curved dislocation bundles passing through the entire crystal are observed, on which precipitates are formed. In the initial part of the crystal, dislocations are located chaotically, while towards the middle of the sample they are aligned along the growth striae. In the final part of the crystal, the dislocation density increases.

Structural Defects in Heteroepitaxial and Homoepitaxial GaN

1995 ◽  
Vol 395 ◽  
Author(s):  
Zuzanna Liliental-Weber ◽  
S. Ruvimov ◽  
CH. Kisielowski ◽  
Y. Chen ◽  
W. Swider ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Buffer Layers ◽  
Structural Defects ◽  
Structural Quality ◽  
Organic Chemical ◽  
Liquid Gallium ◽  
Extended Defects ◽  
X Ray ◽  
Bulk Gan

ABSTRACTThe microstructure and characteristic defects of heteroepitaxial GaN films grown on sapphire using molecular beam epitaxy (MBE) and metal-organic-chemical-vapor-deposition (MOCVD) methods and of homoepitaxial GaN grown on bulk substrates are described based on transmission electron microscopy (TEM), x-ray diffraction, and cathodoluminescence (CL) studies. The difference in arrangement of dislocations along grain boundaries and die influence of buffer layers on the quality of epitaxial films is described. The structural quality of GaN epilayers is compared to diat of bulk GaN crystals grown from dilute solution of atomic nitrogen in liquid gallium. The full width at half maximum (FWHM) of the x-ray rocking curves for these crystals was in the range of 20–30 arc sec, whereas for the heteroepitaxially grown GaN the FWHM was in the range of 5–20 arc min. Homoepitaxial MBE grown films had FWHMs of about 40 arc sec. The best film quality was obtained for homoepitaxial films grown using MOCVD; these samples were almost free from extended defects. For the bulk GaN crystals a substantial difference in crystal perfection was observed for the opposite sides of the plates shaped normal to the c direction. On one side the surface was almost atomically flat, and the underlying material was free of any extended structural defects, while the other side was rough, with a high density of planar defects. This difference was related to the polarity of the crystal. A large difference in crystal stoichiometry was also observed within different sublayers of the crystals. Based on convergent beam electron diffraction and cathodoluminescence, it is proposed that GaN antisite defects are related to the yellow luminescence observed in these crystals.

Crystal Structure Of Lt Gaas Layers Before And After Annealing

1991 ◽  
Vol 241 ◽  
Author(s):  
Zuzanna Liliental-Weber
Keyword(s):  
Growth Temperature ◽  
Growth Conditions ◽  
Structural Defects ◽  
Structural Quality ◽  
Before And After ◽  
Formation Energies ◽  
Insulating Properties ◽  
Minority Carriers

ABSTRACTThe structural quality of GaAs layers grown at low temperatures by solid-source and gassource MBE at different growth conditions is described. Dependence on the growth temperature and concentration of As [expressed as As/Ga beam equivalent pressure (BEP)] used for the growth is discussed. A higher growth temperature is required to obtain the same monocrystalline layer thickness with increased BEP The annealing of these layers is associated with the formation of As precipitates. Semicoherent precipitates with lowest formation energies arc formed in the monocrystalline parts of the layers grown with the lowest BEP. Precipitates with higher bormation energies are formed when higher BEP is applied; they are also formed in the vicinity of structural defects. Formation of As precipitates releases strain in the layers. Arsenic precipitates are not formed in annealed ternary (InAlAs) layers despite their semi-insulating properties. The role of As precipitates in semi-insulating properties and the short lifetime of minority carriers in these layers is discussed.

Raman Scattering from GaAs Nanowires Grown by Molecular Beam Epitaxy

2007 ◽  
Vol 31 ◽  
pp. 23-26 ◽  
Author(s):  
N. Begum ◽  
A.S. Bhatti ◽  
M. Piccin ◽  
G. Bais ◽  
F. Jabeen ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Structural Defects ◽  
Structural Quality ◽  
Spintronic Devices ◽  
Gaas Nanowires ◽  
Potential Applications ◽  
Self Assembled ◽  
Substrate Temperatures

Self-assembled nanowires have attracted much attention due to their potential applications in electronics and optoelectronics. A recent interest in Mn catalyzed GaAs nanowires are due to their potential use in spintronic devices at nanoscale. High densities of Au- and Mncatalyzed self-assembled GaAs nanowires (NWs) with diameter in the range of 20 to 200 nm and length of few microns were synthesized by molecular beam epitaxy (MBE) on different substrates at varied substrate temperatures. These nanowires were investigated by means of μ-Raman spectroscopy at room temperature. The Raman spectra from NWs show an energy downshift and a broadening of the LO and TO phonon lines that differ from those of epitaxial GaAs. We suggest that those downshift and broadening are due to the relaxation of the q=0 selection rule in the presence of structural defects in the nanowires. The results indicate that the use of Mn instead of Au as growth catalyst does not affect the structural quality of the nanowires drastically.

scholarly journals The Role of the Multi Buffer Layer Technique on the Structural Quality of GaN

1999 ◽  
Vol 595 ◽  
Author(s):  
M. Benamara ◽  
Z. Liliental-Weber ◽  
J.H. Mazur ◽  
W. Swider ◽  
J. Washburn ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Buffer Layers ◽  
Structural Quality ◽  
Transmission Electron ◽  
Layer Technique ◽  
Growth Method ◽  
Microscopy Techniques ◽  
Edge Dislocations

AbstractSuccessive growth of thick GaN layers separated by either LT-GaN or LT-AlN interlayers have been investigated by transmission electron microscopy techniques. One of the objectives of this growth method was to improve the quality of GaN layers by reducing the dislocation density at the intermediate buffer layers that act as barriers to dislocation propagation. While the use of LT-AlN results in the multiplication of dislocations in the subsequent GaN layers, the LT-GaN reduces dislocation density. Based upon Burgers vector analysis, the efficiency of the buffer layers for the propagation of the different type of dislocations is presented. LT-AlN layer favor the generation of edge dislocations, leading to a highly defective GaN layer. On the other hand, the use of LT-GaN as intermediate buffer layers appears as a promising method to obtain high quality GaN layer.

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