Development of Cross-Hatch Morphology During Growth of Lattice Mismatched Layers

2001 ◽  
Vol 673 ◽  
Author(s):  
A. Maxwell Andrews ◽  
J.S. Speck ◽  
A.E. Romanov ◽  
M. Bobeth ◽  
W. Pompe
Keyword(s):  
Misfit Dislocation ◽  
Film Growth ◽  
Strain Relaxation ◽  
Dislocation Generation ◽  
Force Microscopy ◽  
Step Flow ◽  
Atomic Force ◽  
Subsequent Step ◽  
Step Flow Growth ◽  
Lateral Scale

ABSTRACTAn approach is developed for understanding the cross-hatch morphology in lattice mismatched heteroepitaxial film growth. It is demonstrated that both strain relaxation associated with misfit dislocation formation and subsequent step elimination (e.g. by step-flow growth) are responsible for the appearance of nanoscopic surface height undulations (0.1-10 nm) on a mesoscopic (∼100 nm) lateral scale. The results of Monte Carlo simulations for dislocation- assisted strain relaxation and subsequent film growth predict the development of cross-hatch patterns with a characteristic surface undulation magnitude ∼50 Å in an approximately 70% strain relaxed In0.25Ga0.75As layers. The model is supported by atomic force microscopy (AFM) observations of cross-hatch morphology in the same composition samples grown well beyond the critical thickness for misfit dislocation generation.

Strain Relaxation at Low Misfits: Dislocation Injection vs. Surface Roughening

1995 ◽  
Vol 399 ◽  
Author(s):  
D.D. Perovic ◽  
B. Bahierathan ◽  
D.C. Houghton ◽  
H. Lafontaine ◽  
J.-M. Baribeau
Keyword(s):  
Misfit Dislocation ◽  
Strain Relaxation ◽  
Relaxation Mechanism ◽  
Theoretical Description ◽  
Dislocation Nucleation ◽  
Surface Roughening ◽  
X Ray Diffraction ◽  
Dislocation Generation ◽  
Force Microscopy ◽  
Atomic Force

ABSTRACTTwo competing strain relaxation mechanisms, namely misfit dislocation generation and surface roughening, have been extensively studied using the GexSi1-x/Si (x< 0.5) system as an example. A predictive model has been developed which accurately describes the nature of misfit dislocation nucleation and growth under non-equilibrium conditions. Using optical and electron microscopy, coupled with a refined theoretical description of dislocation nucleation, it is shown that strain relieving dislocations are readily generated at low misfits with a characteristic activation energy barrier regardless of the growth technique employed (i.e. MBE, RTCVD and UHVCVD). Secondly we have studied the alternative elastic strain relaxation mechanism involving surface undulation; x-ray diffraction, electron and atomic force microscopy have been used to characterize GexSi1-x/Si (x<0.5) structures grown by UHVCVD and MBE at relatively higher temperatures. A theoretical model has been used to model the critical thickness for surface wave generation. The conditions governing the interplay between dislocation formation and surface buckling are described in terms of a "morphological instability diagram".

4H-SiC Homoepitaxial Growth on Substrates with Different Off-Cut Directions

2011 ◽  
Vol 679-680 ◽  
pp. 55-58 ◽  
Author(s):  
Birgit Kallinger ◽  
Bernd Thomas ◽  
Patrick Berwian ◽  
Jochen Friedrich ◽  
Gerd Trachta ◽  
...  
Keyword(s):  
Growth Process ◽  
Screw Dislocations ◽  
Force Microscopy ◽  
Step Flow ◽  
Homoepitaxial Growth ◽  
Atomic Force ◽  
P Type ◽  
Step Flow Growth ◽  
Edge Dislocations ◽  
Doping Range

Homoepitaxial growth on 4° off-axis substrates with different off-cut directions, i.e. [11-20] and [1-100], was investigated using a commercial CVD reactor. The characteristics of the growth process on substrates with different off-cut directions were determined with respect to applicable C/Si ratio, growth rate and n- and p-type doping range. Stable step flow growth was achieved over a broad range of C/Si ratio at growth rates ~ 15 µm/h in both cases. The n-type doping level of epilayers can be controlled at least in the range from 5  1014 cm-3 to 3  1017 cm-3 on both types of substrates. Highly p-type epilayers with p = 2  1019 cm-3 can also be grown on [1-100] off-cut substrates. Hence, the growth process for standard substrates was successfully transferred to [1-100] off-cut substrates resulting in epilayers with similar doping levels. The dislocation content of the grown epilayers was investigated by means of defect selective etching (DSE) in molten KOH. For both off-cut directions of the substrates, similar densities of threading edge dislocations (TED), threading screw dislocations (TSD) and basal plane dislocations (BPD) were found in the epilayers. Epilayers with very low BPD density can be grown on both kinds of substrates. The remaining BPDs in epilayers are inclined along the off-cut direction of the substrate. The surface morphology and roughness was investigated by atomic force microscopy (AFM). The epilayers grown on [1-100] off-cut substrates are smoother than those on standard substrates.

The Initial Stages of Growth of Ordered GaInP and GaInAs Grown by Metal Organic Vapor Phase Epitaxy

1999 ◽  
Vol 583 ◽  
Author(s):  
M. C. Hanna ◽  
A. Mascarenhas ◽  
Hyeonsik M. Cheong
Keyword(s):  
Raman Spectroscopy ◽  
Atomic Force Microscopy ◽  
Direct Evidence ◽  
Force Microscopy ◽  
Step Flow ◽  
Organic Vapor ◽  
Stages Of Growth ◽  
Atomic Force ◽  
Metal Organic ◽  
Step Flow Growth

AbstractWe have used atomic force microscopy (AFM) and Raman spectroscopy to investigate the development of the surface morphology of (001) direct and vicinal GaInP and GaInAs grown under conditions to produce strong CUPtB ordering. Raman spectroscopy provided direct evidence of CuPtB ordering in layers as thin as 10 nm for GaInP and 5 nm for GaInAs. We find that the morphology of GaInP and GaInAs on (001)6B substrates consists of ridges, which are aligned predominately along the [110] direction (A-direction). These ridges are well developed even at layer thicknesses of 2 nm, and their sides consist of step-bunches and near (001) terraces. On (001) direct substrates, the GaInP morphology is similar to that obtained on 6B substrates, although the step bunches have no preferential orientation, while GaInAs (001) growth proceeds by a combination of 2D-island and step flow growth. We discuss possible reasons for the differences in the morphology of ordered GaInP and GaInAs. The results of this work suggest it may be difficult to produce abrupt heterointerfaces in structures containing ordered GalnP and GaInAs alloys.

HVPE and MOVPE GaN Growth on Slightly Misoriented Sapphire Substrates

1999 ◽  
Vol 595 ◽  
Author(s):  
Olivier Parillaud ◽  
Volker Wagner ◽  
Hans-Jörg Bühlmann ◽  
François Lelarge ◽  
Marc Ilegems
Keyword(s):  
Substrate Surface ◽  
Growth Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Step Flow ◽  
Sapphire Substrates ◽  
Atomic Force ◽  
Step Flow Growth ◽  
Gan Buffer Layer

AbstractWe present preliminary results on gallium nitride growth by HVPE on C-plane sapphire with 2, 4 and 6 degrees misorientation towards M and A directions. A nucleation GaN buffer layer is deposited prior the growth by MOVPE. Surface morphology and growth rates are compared with those obtained on exact C-plane oriented sapphire, for various growth conditions. As expected, the steps already present on the substrate surface help to initiate a directed step-flow growth mode. The large hillocks, which are typical for HVPE GaN layers on (0001) sapphire planes, are replaced by more or less parallel macro-steps. The width and height of these steps, due to step bunching effect, depend directly on the angle of misorientation and on the growth conditions, and are clearly visible by optical or scanning electron microscopy. Atomic force microscopy and X-ray diffraction measurements have been carried out to quantify the surface roughness and crystal quality.

Atomic Force Microscopy Study of GaN Grown on Al2O3(0001) by LP-MOVPE

2000 ◽  
Vol 639 ◽  
Author(s):  
K. Xu ◽  
D. H. Lim ◽  
B. L. Liu ◽  
X. L. Du ◽  
G. H. Yu ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Growth Temperature ◽  
Spiral Growth ◽  
Initial Growth ◽  
Growth Mechanisms ◽  
Remarkable Effect ◽  
Force Microscopy ◽  
Step Flow ◽  
Atomic Force ◽  
Step Flow Growth

ABSTRACTThere is currently a high degree of interest in understanding the diverse mechanisms that determine the growth morphology of epitaxial films. To understand and control over these mechanisms, it is essential to know how the growth mechanisms are correlated with morphologies. In GaN MOVPE processes, growth temperature has a remarkable effect on the film morphologies and properties. In present work, the temperature dependency of surface morphology of GaN epilayers grown by low-pressure metal-organic vapor phase epitaxy (LP-MOVPE) was studied using atomic force microscopy. It was demonstrated that dislocations strongly influence the growth mechanisms and the morphology of the films. Three growth modes were identified at different growth temperature ranged from 1030°C to 1100°C, which are, (1) spiral growth dominated by dislocation with screw type, (2) monolayer step flow, and (3) nucleation-assisted step flow growth. The significant effect of dislocation on the surface morphologies and growth mechanisms may be attributed to the high dislocation density and higher activation energy for a step overcoming the dislocation pinning in GaN. Because few dislocations will be introduced under monolayer step flow growth mode, we can infer the useful information about GaN initial growth.

scholarly journals HVPE and MOVPE GaN growth on slightly misoriented sapphire substrates

2000 ◽  
Vol 5 (S1) ◽  
pp. 124-130 ◽  
Author(s):  
Olivier Parillaud ◽  
Volker Wagner ◽  
Hans-Jörg Bühlmann ◽  
François Lelarge ◽  
Marc Ilegems
Keyword(s):  
Substrate Surface ◽  
Growth Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Step Flow ◽  
Sapphire Substrates ◽  
Atomic Force ◽  
Step Flow Growth ◽  
Gan Buffer Layer

We present preliminary results on gallium nitride growth by HVPE on C-plane sapphire with 2, 4 and 6 degrees misorientation towards M and A directions. A nucleation GaN buffer layer is deposited prior the growth by MOVPE. Surface morphology and growth rates are compared with those obtained on exact C-plane oriented sapphire, for various growth conditions. As expected, the steps already present on the substrate surface help to initiate a directed step-flow growth mode. The large hillocks, which are typical for HVPE GaN layers on (0001) sapphire planes, are replaced by more or less parallel macro-steps. The width and height of these steps, due to step bunching effect, depend directly on the angle of misorientation and on the growth conditions, and are clearly visible by optical or scanning electron microscopy. Atomic force microscopy and X-ray diffraction measurements have been carried out to quantify the surface roughness and crystal quality.

Atomic Force Microscopy study of hexagonal boron nitride film growth on 6H-SiC (0001)

2005 ◽  
Vol 202 (1) ◽  
pp. 3-3 ◽  
Author(s):  
Wei Chen ◽  
Kian Ping Loh ◽  
Ming Lin ◽  
Rong Liu ◽  
Andrew T. S. Wee
Keyword(s):  
Atomic Force Microscopy ◽  
Boron Nitride ◽  
Film Growth ◽  
Hexagonal Boron Nitride ◽  
Microscopy Study ◽  
Nitride Film ◽  
Atomic Force Microscopy Study ◽  
Force Microscopy ◽  
Atomic Force

Stress Relaxation in Uniquely Oriented SiGe/Si Epitaxial Layers

1999 ◽  
Vol 594 ◽  
Author(s):  
M. E. Ware ◽  
R. J. Nemanich
Keyword(s):  
Stress Relaxation ◽  
Surface Morphology ◽  
Strain Relaxation ◽  
Epitaxial Layers ◽  
Misfit Dislocations ◽  
Strained Layers ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Deposited Films

AbstractThis study explores stress relaxation of epitaxial SiGe layers grown on Si substrates with unique orientations. The crystallographic orientations of the Si substrates used were off-axis from the (001) plane towards the (111) plane by angles, θ = 0, 10, and 22 degrees. We have grown 100nm thick Si(1−x) Ge(x) epitaxial layers with x=0.3 on the Si substrates to examine the relaxation process. The as-deposited films are metastable to the formation of strain relaxing misfit dislocations, and thermal annealing is used to obtain highly relaxed films for comparison. Raman spectroscopy has been used to measure the strain relaxation, and atomic force microscopy has been used to explore the development of surface morphology. The Raman scattering indicated that the strain in the as-deposited films is dependent on the substrate orientation with strained layers grown on Si with 0 and 22 degree orientations while highly relaxed films were grown on the 10 degree substrate. The surface morphology also differed for the substrate orientations. The 10 degree surface is relatively smooth with hut shaped structures oriented at predicted angles relative to the step edges.

Highly Oriented Diamond Film Growth by Atomic Force Microscopy

1998 ◽  
Vol 15 (11) ◽  
pp. 822-824 ◽  
Author(s):  
Jian-long Li ◽  
Ge Meng ◽  
Ke-hui Wu ◽  
En-ge Wang
Keyword(s):  
Atomic Force Microscopy ◽  
Diamond Film ◽  
Film Growth ◽  
Force Microscopy ◽  
Atomic Force ◽  
Diamond Film Growth

Transparent Conducting Indium-Tin-Oxide Thin Film with Extremely Flatted Surface

2001 ◽  
Vol 666 ◽  
Author(s):  
Hiromichi Ohta ◽  
Masahiro Orita ◽  
Masahiro Hirano ◽  
Hideo Hosono
Keyword(s):  
Thin Film ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Film Growth ◽  
Oxide Thin Film ◽  
Force Microscopy ◽  
Atomic Force ◽  
Out Of Plane ◽  
Key Factor ◽  
Surface Microstructures

ABSTRACTIndium-tin-oxide films were grown hetero-epitaxially on YSZ surface at a substrate temperature of 900 °C, and their surface microstructures were observed by using atomic force microscopy. ITO films grown on (111) surface of YSZ exhibited very high crystal quality; full width at half maximum of out-of-plane rocking curve was 54 second. The ITO was grown spirally, with flat terraces and steps corresponding to (222) plane spacing of 0.29 nm. Oxygen pressure during film growth is another key factor to obtain atomically flat surfaced ITO thin film.

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