Coarsening and Slope Selection During Crystal Growth and Etching of Ge(001)

1995 ◽  
Vol 399 ◽  
Author(s):  
S. Jay Chey ◽  
Joseph E. Van Nostrand ◽  
David G. Cahill
Keyword(s):  
Surface Roughness ◽  
Crystal Growth ◽  
Molecular Beam ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Low Aspect Ratio ◽  
Wide Range ◽  
Slope Selection ◽  
Low Energy Ions

ABSTRACTThe evolution of surface morphology during low temperature crystal growth by molecular beam epitaxy and etching by low-energy ions is characterized by in-situ scanning tunneling microscopy. Epitaxial growth of Ge(001) at low temperatures in the vicinity of 155°C produces a pattern of growth mounds while etching at temperatures near 270°C produces a pattern of low aspect ratio pits. The characteristic in-plane length scale of the surface roughness d increase with a power law dependence on time but the exponent depends on temperature and process. Prior to the onset of amorphous growth, the amplitude of the surface roughness G1/2(d/2) increases more rapidly than d; i.e. the slope of the sides of the growth mounds increases with time. By contrast, the ratio of Gl/2(d/2) to d remains nearly constant during ion etching for a wide range of etching times.

STM studies of crystal growth

1991 ◽  
Vol 49 ◽  
pp. 374-375
Author(s):  
M. G. Lagally
Keyword(s):  
Crystal Growth ◽  
Molecular Beam ◽  
Chemical Vapor ◽  
Sputter Deposition ◽  
Field Of View ◽  
Scanning Tunneling ◽  
Wide Field ◽  
Tunneling Microscopy ◽  
Wide Field Of View ◽  
The One

It has been recognized since the earliest days of crystal growth that kinetic processes of all Kinds control the nature of the growth. As the technology of crystal growth has become ever more refined, with the advent of such atomistic processes as molecular beam epitaxy, chemical vapor deposition, sputter deposition, and plasma enhanced techniques for the creation of “crystals” as little as one or a few atomic layers thick, multilayer structures, and novel materials combinations, the need to understand the mechanisms controlling the growth process is becoming more critical. Unfortunately, available techniques have not lent themselves well to obtaining a truly microscopic picture of such processes. Because of its atomic resolution on the one hand, and the achievable wide field of view on the other (of the order of micrometers) scanning tunneling microscopy (STM) gives us this opportunity. In this talk, we briefly review the types of growth kinetics measurements that can be made using STM. The use of STM for studies of kinetics is one of the more recent applications of what is itself still a very young field.

Ge-Quantum Dots on SI(001) Tailored by Carbon Predeposition

1998 ◽  
Vol 533 ◽  
Author(s):  
O. Leifeld ◽  
D. Grützmacher ◽  
B. Müller ◽  
K. Kern
Keyword(s):  
Surface Roughness ◽  
Critical Thickness ◽  
Carbon Deposition ◽  
Compressive Strain ◽  
Second Step ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Island Nucleation ◽  
Facet Formation

AbstractThe morphology of Si(001) after carbon deposition of 0.05 to 0.11 monolayers (ML) was investigated in situ by ultrahigh vacuum scanning tunneling microscopy (UHV-STM). The carbon induces a c(4×4)-reconstruction of the surface. In addition, carbon increases the surface roughness compared to clean Si(001) (2×1). In a second step, the influence of the carbon induced restructuring on Ge-island nucleation was investigated. The 3D-growth sets in at considerably lower Ge coverage compared to the clean Si(001) (2×1) surface. This leads to a high density of small though irregularly shaped dots, consisting of stepped terraces, already at 2.5 ML Ge. Increasing the Ge-coverage beyond the critical thickness for facet formation, the dots show { 105 }- facets well known from Ge-clusters on bare Si(001) (2×1). However, they are flat on top with a (001)-facet showing the typical buckled Ge rows and missing dimers. This indicates that the compressive strain is not fully relaxed in these hut clusters.

Using a Moderate Vacuum, Hot/Cryo-Stage Equipped AFM for In-Situ Observation of α-Phase Growth In 60SN40PB Hypoeutectic Solder

1998 ◽  
Vol 4 (S2) ◽  
pp. 316-317
Author(s):  
D. N. Leonard ◽  
P.E. Russell
Keyword(s):  
Surface Science ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
In Situ Observation ◽  
Atmospheric Conditions ◽  
Tunneling Microscopy ◽  
Wide Range ◽  
Gas Environment

Atomic force microscopy (AFM) was introduced in 1984, and proved to be more versatile than scanning tunneling microscopy (STM) due to the AFM's capabilities to scan non-conductive samples under atmospheric conditions and achieve atomic resolution. Ultra high vacuum (UHV) AFM has been used in surface science applications when control of oxidation and corrosion of a sample's surface are required. Expensive equipment and time consuming sample exchanges are two drawbacks of the UHV AFM system that limit its use. Until recently, no hot/cryo-stage, moderate vacuum, controlled gas environment AFM was commonly available.We have demonstrated that phase transformations are easily observable in metal alloys and polymers with the use of a moderate vacuum AFM that has in-situ heating/cooling capabilities and quick (within minutes) sample exchange times. This talk will describe the results of experiments involving a wide range of samples designed to make use of the full capabilities of a hot/cryo-stage, controlled gas environment AFM.

Self-Assembled InAs Islands on (AI,Ga)As, an In Situ Scanning Tunneling Microscopy Study

1999 ◽  
Vol 571 ◽  
Author(s):  
P. Ballet ◽  
J.B. Smathers ◽  
G.J. Salamo
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Molecular Beam ◽  
Three Dimensional ◽  
Microscopy Study ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Self Organized ◽  
Scanning Tunneling Microscopy Study ◽  
Island Density

ABSTRACTWe report an in-situ molecular beam epitaxy – scanning tunneling microscopy study of three dimensional (3D) self organized InAs islands on (AI,Ga)As surfaces. The influence of the presence of Al atoms on the roughness of the starting surface and on the island density is shown by investigating several Al compositions. We emphasize the case of InAs/AlAs and point out the major differences between this system and the widely studied InAs/GaAs system.

Observation of Heteroepitaxially Grown Organic Ultrathin Layers on Inorganic Substrates by In Situ RHEED and by STM

1989 ◽  
Vol 159 ◽  
Author(s):  
Masahiko Hara ◽  
Hiroyuki Sasabe ◽  
Akira Yamada ◽  
Anthony F. Garito
Keyword(s):  
Molecular Beam ◽  
Structural Investigation ◽  
Copper Phthalocyanine ◽  
High Energy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
System A ◽  
Ultrathin Layers ◽  
Inorganic Substrates

ABSTRACTAn organic molecular beam epitaxy (OMBE) system has been designed and constructed with in situ reflection high-energy electron diffraction (RHEED) specifically for the deposition of organic molefelar layers under ultrahigh vacuum (UHV), the order of 10–10 torr. The system is equipped with a portable UHV chamber which allows easy transfer of the OMBE film samples to a separate UHV scanning tunneling microscopy (STM) system. A structural investigation of heteroepitaxially grown organic ultrathin layers of copper phthalocyanine (CuPc) on inorganic substrates was carried out by the combined UHV system from less than a monolayer of CuPc.

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