Molecular beam epitaxial growth of III-V semiconductor ... - KOBRA

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Heteroepitaxial Growth of III-V Semiconductor on Silicon Substrates be denoted as ABCABACBA. There is a change in crystal orientation at the twinning plane. Here the normal crystal and its twin share a single plane of atoms (the twinning plane or composition plane) and there is reection symmetry about the twinning plane as shown in Fig. 3.12. In other words, the MTs defect occurs when the stacking faults sequence is disturbed in such a way as to create a mirror image of itself, as in ABCABCCBAACBA [31]. Twinning involves a change in long-range order of the crystal; it therefore cannot result from the simple insertion or removal of an atomic plane, as in the case of the stacking fault. Therefore, twins cannot be created by the glide of dislocations. Instead, twinning occurs during crystal growth, either bulk growth or heteroepitaxy. Finding ways to reduce the density of dislocations at a given mismatch starin level is an important goal for successful strained-layer heteroepitaxy. As mentioned before, dislocations and defects can act as non-radiative recombination centers in optoelectronic devices, because the localized mid-bandgap energy levels in the dislocations cores will act as highly ecient trap states for injected minority carriers [14]. A great volume of research activities has already been dedicated to the various barriers to III-V integration on silicon. Nevertheless, it has yet to be shown the quality of III-V on Si material can oer reliability and performance demanded optoelectronic and other device applications. In this research work, a new approach for III-V on silicon heterepitaxy based on self-assembled and localized growth of nanostructures like quantum dots and dashes will be investigated. The idea is to minimize the above mentioned problems of the formation of dislocations during the growth of relaxation layers. However, the materials integration processes were conducted by the means of the epitaxial growth of III-V quantum dots and dashes on silicon substrates via MBE technique, using the most challenging materials integration approach, by limiting the III-V material to the active region. 48
Chapter 4 Experimental Growth and Characterization Techniques 4.1 Overview The growth and characterization techniques of the III-V on Si samples produced for the work reported in this thesis, will be discussed in this chapter. However, all the samples in this research work were grown by the ultra-high vacuum solid-state molecular beam epitaxy (UHV-SMBE) technique. This research work required also a variety of characterization techniques, serving as a reference for better interpretation and understanding of the experimental results. Molecular beam epitaxy and ultra-high vacuum (UHV) technology were key components achieving successful epitaxial growth. Reection high energy electron diraction (RHEED) was used to check the silicon surface substrate preparation and the formation of the quantum dots. The structural analysis of the grown samples, was conducted using atomic force microscopy (AFM), high resolution transmission electron microscopy (HR-TEM), high resolution X-ray diraction (HR-XRD) and secondary electron microscopy (SEM). 49
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Molecular Beam Epitaxial Growth of
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Gutachter (Supervisors): 1. Prof. D
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patterns indicating a 2D smooth sur
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(MEE = migration enhance epitaxy) u
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Page 12 and 13: CONTENTS 3.4.4 Planar Defects Assoc
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Page 16 and 17: Introduction thesis a detailed stud
Page 18 and 19: Introduction 1.1.2 Thesis Approach
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Page 22 and 23: Theoretical Background of Semicondu
Page 36 and 37: Heteroepitaxial Growth of III-V Sem
Page 64 and 65: Experimental Growth and Characteriz
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MBE Growth of Self-Assembled InAs a
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MBE Growth of InAs and InGaAs Quant
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Optimization of MEE and MBE growth
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Conclusions substrates, respectivel
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REFERENCES [8] J. M. Gerard, O. Cab
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REFERENCES [29] http://www.wmi.badw
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REFERENCES [49] M. R. Brenner: GaP/
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REFERENCES [66] Y. Ishida, T. Takah
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REFERENCES [84] A. Garcia, C. M. Ma
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REFERENCES [100] M. Felici, P. Gall
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REFERENCES [116] H. Usui, H. Yasuda
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REFERENCES [133] Grassman, T. J. Br
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Conferences Contributions: Tariq Al
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Nomenclature
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REFERENCES symbol Descriptions γ f
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like to thank all member of the Ins
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REFERENCES Erklärung Hiermit versi
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Molecular beam epitaxial growth of III-V semiconductor ... - KOBRA

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