Structural and Electrical Characterization of Si-Modfet Structures Grown at High Rates by Lepecvd

AbstractStrain relaxed graded SiGe buffer layers have been grown by low energy plasma enhanced chemical vapour deposition (LEPECVD). Due to the low ion energies involved in LEPECVD, exceptionally high plasma intensities can be applied without any ion damage of the epitaxial layers. Transmission electron microscopy and X-ray reciprocal space mapping show that relaxed buffer layers grown at rates exceeding 5 nm/s are of a comparable quality to buffer layers grown by standard techniques at much lower rates. Low temperature electric transport measurements on remotely doped tensilely strained Si quantum wells synthesized by LEPECVD show that also good electrical quality is achieved.

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Spontaneous Lateral Modulations in InAlAs Buffer Layers Grown by MBE on InP Substrates

MRS Proceedings ◽

10.1557/proc-417-265 ◽

1995 ◽

Vol 417 ◽

Cited By ~ 6

Author(s):

F. Peiró ◽

A. Cornet ◽

J. C. Ferrer ◽

J. R. Morante ◽

G. Halkias ◽

...

Keyword(s):

Quantum Wells ◽

Molecular Beam ◽

Buffer Layers ◽

Single Quantum ◽

X Ray Diffraction ◽

Single Quantum Well ◽

Quantum Well Structures ◽

X Ray ◽

Transmission Electron ◽

Inp Substrates

AbstractTransmission Electron Microscopy (TEM) and X-ray Diffraction (XRD) have been used to analyze the spontaneous appearance of lateral composition modulations in InyAl1−yAs (yIn.≅ 50%) buffer layers of single quantum well structures grown by molecular beam epitaxy on exact and vicinal (100) InP substrates, at growth temperatures in the range of 530°C–580°C. The influence of the growth temperature, substrate misorientation and epilayer mismatch on the InAlAs lateral modulation is discussed. The development of a self-induced quantum-wire like morphology in the In0.53Ga0.47As single quantum wells grown over the modulated buffers is also commented on.

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Optical and structural analysis of Ge quantum dots embedded in strained Si quantum wells grown on patterned substrates

MRS Proceedings ◽

10.1557/proc-638-f14.8.1 ◽

2000 ◽

Vol 638 ◽

Author(s):

A. Beyer ◽

E. Müller ◽

H. Sigg ◽

S. Stutz ◽

C. David ◽

...

Keyword(s):

Quantum Dots ◽

Quantum Wells ◽

Experimental Parameter ◽

Buffer Layers ◽

Patterned Substrates ◽

Strained Si ◽

Cross Sectional ◽

Strong Localization ◽

Ge Quantum Dots ◽

Indirect Band Gap

AbstractGermanium quantum dots embedded in silicon have been used in the past to improve the opto-electronic properties of Si based materials. The idea is to overcome the limitation of the indirect band gap of Si by a strong localization of the carriers in quantum dots. However, the Ge quantum dots provide a strong carrier confinement only for the holes, the electrons are only weakly confined in the Si. In this study we embedded the Ge quantum dots in strained Si quantum wells grown on relaxed SiGe buffer layers. The strained Si quantum wells provide a confinement of the electrons in the vicinity of the Ge dots.The structures were deposited on planar as well as on patterned substrates by molecular beam epitaxy. The structural and optical properties of the samples were analyzed using high resolution cross sectional transmission electron microscopy (TEM) as well as low temperature photoluminescence. The size of the mesa structures have been used as experimental parameter. Relaxed buffer layers grown on line shaped mesa structures show a strongly reduced dislocation density. Consequently the deep luminescence attributed to dislocations in the buffer layers is strongly reduced and pronounced photoluminescence of the quantum structures grown on top of the buffer layers can be observed.

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Thermal Stability of Strained Si on Relaxed Si1−xGex Buffer Layers

MRS Proceedings ◽

10.1557/proc-686-a1.2 ◽

2001 ◽

Vol 686 ◽

Cited By ~ 1

Author(s):

P.M. Mooney ◽

S.J. Koester ◽

J.A. Ott ◽

J.L. Jordan-Sweet ◽

J.O. Chu ◽

...

Keyword(s):

Thermal Stability ◽

Layer Thickness ◽

Buffer Layers ◽

Misfit Dislocations ◽

X Ray Diffraction ◽

Strained Si ◽

X Ray ◽

Dislocation Glide ◽

Transmission Electron ◽

Thermal Stability Of

AbstractThe thermal stability of strained Si on relaxed Si1−xGex structures annealed at 1000 °C was investigated using high-resolution x-ray diffraction, Raman spectroscopy and transmission electron microscopy. Interdiffusion at the Si/Si1−xGex interface is negligible for annealing times <30 sec and is independent of the initial Si layer thickness and the composition of the Si1−xGex layer. In all cases the Si layers remained nearly fully strained, but a significant density of misfit dislocations was seen in layers that exceeded the critical thickness for dislocation glide. The Si layer thickness could be measured for layers as thin as 7 nm.

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Characterisation of Extended Defects in Si and Si1−x Gex Alloys: The Influence of Transition Metal Contamination

MRS Proceedings ◽

10.1557/proc-263-305 ◽

1992 ◽

Vol 263 ◽

Cited By ~ 1

Author(s):

V. Higgs ◽

E.C. Lightowlers

Keyword(s):

Chemical Vapour ◽

Buffer Layers ◽

Band Pass Filter ◽

Misfit Dislocations ◽

Extended Defects ◽

Pass Filter ◽

Slip Lines ◽

Pl Spectra ◽

Transmission Electron ◽

Cu Contamination

ABSTRACTPhotoluminescence (PL) spectroscopy, cathodoluminescence (CL) spectroscopy and imaging, transmission electron microscopy (TEM), and preferential defect etching and optical microscopy have been used to characterise dislocations in plastically deformed Si and in Si1−x Gex alloys. The PL spectra from plastically deformed Si produced under clean conditions, contained no dislocation related luminescence features. However, after deliberated Cu contamination and annealing, the PL spectra were dominated by the four main D-bands (D1-D4). CL spectroscopy and imaging revealed that the D3 and D4 bands originate on the slip lines, whereas D1 and D2 are dominant between the slip lines. Pseudomorphic Si1−x Gex layers grown by molecular beam epitaxy (MBE) and forced to relax by Cu contamination and annealing have also been examined. Both the PL and CL spectra were dominated by the D1-D4 bands, and monochromatic CL imaging showed that the D3 and D4 bands originate at the misfit dislocations with the location of the Dl and D2 bands being much less well defined. PL spectra from Si1−x Gex capping layers, grown by MBE on linearly compositionally graded buffer layers, were dominated by bound exciton luminescence features, identical with those observed in bulk grown alloys, and showed relatively weak D-band features. PL spectra obtained after chemical step etching, and CL spectra obtained with different beam energies, showed that the D-bands originated in the buffer layers which contained high densities of misfit dislocations. Well defined monochromatic CL images of the misfit dislocations could only be obtained using a narrow band pass filter centred on the D4 band. No D-band luminescence was observed from Si1−x Gex layers grown by high temperature chemical vapour deposition (CVD). However, after deliberate contamination with Ni, the D-bands became the dominant features and CL imaging clearly showed that the D4 band originates at the misfit dislocations and the D2 band predominantly between the misfit dislocations.

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Low Energy Plasma Enhanced Chemical Vapour Deposition - Plasma Enhanced Deposition of Epitaxial Si and Sige

MRS Proceedings ◽

10.1557/proc-696-n4.7 ◽

2001 ◽

Vol 696 ◽

Author(s):

Carsten Rosenblad ◽

Matthias Kummera ◽

Hans-Rudolf Deller ◽

Thomas Graf ◽

Alex Dommann ◽

...

Keyword(s):

Chemical Vapour Deposition ◽

Vapour Deposition ◽

Chemical Vapour ◽

High Growth ◽

Hole Mobility ◽

High Plasma ◽

Low Energy ◽

Buffer Layers ◽

Wafer Surface ◽

Growth Time

AbstractLow energy plasma enhanced chemical vapour deposition (LEPECVD) is a deposition technique developed for the epitaxy of Si and SiGe at ultra-high deposition rates. Due to a high current plasma discharge composed of low energy particles, a high plasma enhancement can be obtained without any accompanying plasma induced damage of the wafer surface. The most important application of LEPECVD so far is for compositionally graded relaxed SiGe buffer layers. Such relaxed buffer layers are demonstrated with end composition up to pure Ge and with a growth time below 1 hour. A p-type hetero-MOSFET formed in a SiGe channel compressively strained to a Si0.5Ge0.5 relaxed buffer layer, is demonstrated as one example where the high growth rates of LEPECVD allows the synthesis of devices which cannot be produced with an acceptable throughput with conventional deposition methods. The room temperature effective hole mobility of 760 cm2/Vs obtained on such devices demonstrates a high structural and electrical quality of the LEPECVD material.

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Characterisation of multilayer materials using a position-sensitive atom probe

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176253 ◽

1990 ◽

Vol 48 (4) ◽

pp. 624-625

Author(s):

RAD Mackenzie ◽

G D W Smith ◽

A. Cerezo ◽

J A Liddle ◽

CRM Grovenor ◽

...

Keyword(s):

Quantum Well ◽

Quantum Wells ◽

Spatial Information ◽

Chemical Vapour ◽

Atom Probe ◽

Organic Chemical ◽

Growth Stages ◽

Multiple Quantum ◽

Quartz Wool ◽

Position Sensitive

The position sensitive atom probe (POSAP), described briefly elsewhere in these proceedings, permits both chemical and spatial information in three dimensions to be recorded from a small volume of material. This technique is particularly applicable to situations where there are fine scale variations in composition present in the material under investigation. We report the application of the POSAP to the characterisation of semiconductor multiple quantum wells and metallic multilayers.The application of devices prepared from quantum well materials depends on the ability to accurately control both the quantum well composition and the quality of the interfaces between the well and barrier layers. A series of metal organic chemical vapour deposition (MOCVD) grown GaInAs-InP quantum wells were examined after being prepared under three different growth conditions. These samples were observed using the POSAP in order to study both the composition of the wells and the interface morphology. The first set of wells examined were prepared in a conventional reactor to which a quartz wool baffle had been added to promote gas intermixing. The effect of this was to hold a volume of gas within the chamber between growth stages, leading to a structure where the wells had a composition of GalnAsP lattice matched to the InP barriers, and where the interfaces were very indistinct. A POSAP image showing a well in this sample is shown in figure 1. The second set of wells were grown in the same reactor but with the quartz wool baffle removed. This set of wells were much better defined, as can be seen in figure 2, and the wells were much closer to the intended composition, but still with measurable levels of phosphorus. The final set of wells examined were prepared in a reactor where the design had the effect of minimizing the recirculating volume of gas. In this case there was again further improvement in the well quality. It also appears that the left hand side of the well in figure 2 is more abrupt than the right hand side, indicating that the switchover at this interface from barrier to well growth is more abrupt than the switchover at the other interface.

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The Electrical Characterization and Physical Failure Analysis for Transistor Gate Leakage

ISTFA 2006: Conference Proceedings from the 32nd International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2006p0257 ◽

2006 ◽

Author(s):

Tsung-Te Li ◽

Chao-Chi Wu ◽

Jung-Hsiang Chuang ◽

Jon C. Lee

Keyword(s):

Failure Analysis ◽

Electrical Characterization ◽

Physical Analysis ◽

Gate Leakage ◽

Force Microscopy ◽

Atomic Force ◽

Transmission Electron ◽

Voltage Stress ◽

Leakage Site

Abstract This article describes the electrical and physical analysis of gate leakage in nanometer transistors using conducting atomic force microscopy (C-AFM), nano-probing, transmission electron microscopy (TEM), and chemical decoration on simulated overstressed devices. A failure analysis case study involving a soft single bit failure is detailed. Following the nano-probing analysis, TEM cross sectioning of this failing device was performed. A voltage bias was applied to exaggerate the gate leakage site. Following this deliberate voltage overstress, a solution of boiling 10%wt KOH was used to etch decorate the gate leakage site followed by SEM inspection. Different transistor leakage behaviors can be identified with nano-probing measurements and then compared with simulation data for increased confidence in the failure analysis result. Nano-probing can be used to apply voltage stress on a transistor or a leakage path to worsen the weak point and then observe the leakage site easier.

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The impact of point defects in n-type GaN layers on thermal decomposition of InGaN/GaN QWs

Scientific Reports ◽

10.1038/s41598-021-81017-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mikolaj Grabowski ◽

Ewa Grzanka ◽

Szymon Grzanka ◽

Artur Lachowski ◽

Julita Smalc-Koziorowska ◽

...

Keyword(s):

Quantum Wells ◽

High Temperatures ◽

Point Defects ◽

X Ray Diffraction ◽

Helium Ions ◽

X Ray ◽

Sapphire Substrates ◽

Transmission Electron ◽

The Impact ◽

Ingan Quantum Wells

AbstractThe aim of this paper is to give an experimental evidence that point defects (most probably gallium vacancies) induce decomposition of InGaN quantum wells (QWs) at high temperatures. In the experiment performed, we implanted GaN:Si/sapphire substrates with helium ions in order to introduce a high density of point defects. Then, we grew InGaN QWs on such substrates at temperature of 730 °C, what caused elimination of most (but not all) of the implantation-induced point defects expanding the crystal lattice. The InGaN QWs were almost identical to those grown on unimplanted GaN substrates. In the next step of the experiment, we annealed samples grown on unimplanted and implanted GaN at temperatures of 900 °C, 920 °C and 940 °C for half an hour. The samples were examined using Photoluminescence, X-ray Diffraction and Transmission Electron Microscopy. We found out that the decomposition of InGaN QWs started at lower temperatures for the samples grown on the implanted GaN substrates what provides a strong experimental support that point defects play important role in InGaN decomposition at high temperatures.

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