Strain relaxation of InxGa1−xAs during lateral oxidation of underlying AlAs layers

AbstractWe demonstrate a new approach to the growth of dislocation free lattice-mismatched materials on GaAs substrates using Al2O3 interlayers obtained by lateral oxidation of AlAs. This is achieved by generating relaxed low threading dislocation density InGaAs templates which are mechanically supported but epitaxially decoupled from the host GaAs substrate. This process uses the phenomena of relaxation of strained coherent hypercritical thickness (h > hcritical,) layer in direct contact with an oxidizing Al-containing semiconductor (i.e. AlAs or AlGaAs). 5000 Å In0.11Ga0.89As layers were then grown on the In0.2 Ga0.8As/Al2O3/GaAs template which acts as a pseudo-substrate (lattice-engineered substrate). The epitaxial layers are partially relaxed and have extremely smooth surface morphology. Further TEM micrographs of these epitaxial layers show no misfit dislocations or related localized strain fields at the In0.2Ga0.8As/Al2O3 interface. The absence of misfit dislocations or local strain contrast at the In0.2Ga0.8As/Al2O3 interface is attributed to both reactive material removal during the oxidation process and the porous nature of the oxide itself. We propose that the strain relaxation in In0.3Ga0.7As is enhanced due to the absence of misfit dislocations at the In0.2Ga0.8As/A12O3 interface.

Download Full-text

TEM study of phosphorus-implanted pseudomorphic Si0.88Ge0.12 on Si(100)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100138713 ◽

1995 ◽

Vol 53 ◽

pp. 468-469

Author(s):

N. David Theodore ◽

Donald Y.C Lie ◽

J. H. Song ◽

Peter Crozier

Keyword(s):

Integrated Circuits ◽

Heterojunction Bipolar Transistors ◽

Integrated Circuit ◽

High Speed ◽

Room Temperature ◽

Strain Relaxation ◽

Bipolar Transistors ◽

Sige Hbt ◽

Integrated Circuit Manufacturing ◽

Microstructural Behavior

SiGe is being extensively investigated for use in heterojunction bipolar-transistors (HBT) and high-speed integrated circuits. The material offers adjustable bandgaps, improved carrier mobilities over Si homostructures, and compatibility with Si-based integrated-circuit manufacturing. SiGe HBT performance can be improved by increasing the base-doping or by widening the base link-region by ion implantation. A problem that arises however is that implantation can enhance strain-relaxation of SiGe/Si.Furthermore, once misfit or threading dislocations result, the defects can give rise to recombination-generation in depletion regions of semiconductor devices. It is of relevance therefore to study the damage and anneal behavior of implanted SiGe layers. The present study investigates the microstructural behavior of phosphorus implanted pseudomorphic metastable Si0.88Ge0.12 films on silicon, exposed to various anneals.Metastable pseudomorphic Si0.88Ge0.12 films were grown ~265 nm thick on a silicon wafer by molecular-beam epitaxy. Pieces of this wafer were then implanted at room temperature with 100 keV phosphorus ions to a dose of 1.5×1015 cm-2.

Download Full-text

Strain Relaxation and In-Situ Observation of Voiding in Passivated Aluminum Alloy Lines.

MRS Proceedings ◽

10.1557/proc-308-249 ◽

1993 ◽

Vol 308 ◽

Cited By ~ 3

Author(s):

Paul R. Besser ◽

Thomas N. Marieb ◽

John C. Bravman

Keyword(s):

Strain Relaxation ◽

Grazing Incidence ◽

Scanning Transmission Electron Microscope ◽

In Situ Observation ◽

X Ray ◽

Scanning Transmission ◽

Length Width ◽

Measured Strain ◽

Ray Geometry

ABSTRACTStrain relaxation in passivated Al-0.5% Cu lines was measured using X-ray diffraction coupled with in-situ observation of the formation and growth of stress induced voids. Samples of 1 μm thick Al-0.5% Cu lines passivated with Si3N4 were heated to 380ºC, then cooled and held at 150ºC. During the test, principal strains along the length, width, and height of the line were determined using a grazing incidence x-ray geometry. From these measurements the hydrostatic strain in the metal was calculated and strain relaxation was observed. The thermal cycle was duplicated in a high voltage scanning transmission electron microscope equipped with a backscattered electron detector. The 1.25 μm wide lines were seen to have initial stress voids. Upon heating these voids reduced in size until no longer observable. Once the samples were cooled to 150ºC, voids reappeared and grew. The measured strain relaxation is discussed in terms of void and θ-phase (Al2Cu) formation.

Download Full-text

Strain Relaxation in (CdMg)Te Layers Grown by Molecular Beam Epitaxy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.182-184.255 ◽

1995 ◽

Vol 182-184 ◽

pp. 255-258

Author(s):

H. Heinke ◽

Franz Dieter Fischer ◽

A. Waag ◽

T. Litz ◽

M. Korn ◽

...

Keyword(s):

Molecular Beam Epitaxy ◽

Molecular Beam ◽

Strain Relaxation

Download Full-text

Void-mediated coherency-strain relaxation and impediment of cubic-to-hexagonal transformation in epitaxial metastable metal/semiconductor TiN/Al0.72Sc0.28N multilayers

Physical Review Materials ◽

10.1103/physrevmaterials.1.033402 ◽

2017 ◽

Vol 1 (3) ◽

Cited By ~ 5

Author(s):

Magnus Garbrecht ◽

Lars Hultman ◽

Mohammed H. Fawey ◽

Timothy D. Sands ◽

Bivas Saha

Keyword(s):

Strain Relaxation ◽

Coherency Strain

Download Full-text

Controlling Strain Relaxation by Interface Design in Highly Lattice-Mismatched Heterostructure

Nano Letters ◽

10.1021/acs.nanolett.1c01938 ◽

2021 ◽

Author(s):

Yang Zhang ◽

Wenlong Si ◽

Yanli Jia ◽

Pu Yu ◽

Rong Yu ◽

...

Keyword(s):

Interface Design ◽

Strain Relaxation

Download Full-text

Improved Performance of GaN-Based Light-Emitting Diodes Grown on Si (111) Substrates with NH3 Growth Interruption

Micromachines ◽

10.3390/mi12040399 ◽

2021 ◽

Vol 12 (4) ◽

pp. 399

Author(s):

Sang-Jo Kim ◽

Semi Oh ◽

Kwang-Jae Lee ◽

Sohyeon Kim ◽

Kyoung-Kook Kim

Keyword(s):

Buffer Layer ◽

Light Emitting Diodes ◽

Defect Density ◽

Strain Relaxation ◽

Multiple Quantum Well ◽

Light Output ◽

Multiple Quantum ◽

Light Emitting ◽

Growth Interruption ◽

Aln Buffer

We demonstrate the highly efficient, GaN-based, multiple-quantum-well light-emitting diodes (LEDs) grown on Si (111) substrates embedded with the AlN buffer layer using NH3 growth interruption. Analysis of the materials by the X-ray diffraction omega scan and transmission electron microscopy revealed a remarkable improvement in the crystalline quality of the GaN layer with the AlN buffer layer using NH3 growth interruption. This improvement originated from the decreased dislocation densities and coalescence-related defects of the GaN layer that arose from the increased Al migration time. The photoluminescence peak positions and Raman spectra indicate that the internal tensile strain of the GaN layer is effectively relaxed without generating cracks. The LEDs embedded with an AlN buffer layer using NH3 growth interruption at 300 mA exhibited 40.9% higher light output power than that of the reference LED embedded with the AlN buffer layer without NH3 growth interruption. These high performances are attributed to an increased radiative recombination rate owing to the low defect density and strain relaxation in the GaN epilayer.

Download Full-text