Surface Instability and Associated Roughness of Pendeo-epitaxy GaN (0001) Films Grown via Metalorganic Vapor Phase Epitaxy

2001 ◽  
Vol 693 ◽  
Author(s):  
Amy M. Roskowski ◽  
Peter Q. Miraglia ◽  
Edward A. Preble ◽  
Sven Einfeldt ◽  
Robert F. Davis
Keyword(s):  
Smooth Surface ◽  
Growth Process ◽  
Root Mean Square Roughness ◽  
Optimum Temperature ◽  
Force Microscopy ◽  
Atomic Force ◽  
Process Route ◽  
Vertical Growth Rate ◽  
Hillock Growth ◽  
Sidewall Surface

AbstractA growth process route that results in thin film GaN templates with a smooth surface morphology at the optimum temperature of 1020°C has been developed. Atomic force microscopy (AFM) reveals hillocks on films grown above 1020°C. Hillocks resulted from the rotation of heterogeneous steps formed at pure screw or mixed dislocations which terminated on the (0001) surface. Growth of the latter feature was controlled kinetically by temperature through adatom diffusion. The 106 cm-2 density of the hillocks was reduced through growth on thick GaN templates and regions of pendeo-epitaxy (PE) overgrowth with lower pure screw or mixed dislocations. Smooth PE surfaces were obtained at temperatures that reduced the lateral to vertical growth rate but also retarded hillock growth that originated in the stripe regions. The (1120 ) PE sidewall surface was atomically smooth, with a root mean square roughness value of 0.17 nm which was the noise limited resolution of the AFM measurements.

The Reactive Formation of Diblock Copolymer at a Polymer/Polymer Interface and its Effect on Interfacial Structure

2000 ◽  
Vol 629 ◽  
Author(s):  
Jonathan S. Schulze ◽  
Timothy P. Lodge ◽  
Christopher W. Macosko
Keyword(s):  
Molecular Weight ◽  
Interfacial Structure ◽  
Root Mean Square Roughness ◽  
Radius Of Gyration ◽  
Interfacial Region ◽  
Force Microscopy ◽  
Amino Terminal ◽  
Polymer Interface ◽  
Atomic Force ◽  
Time Required

ABSTRACTThe reaction of perdeuterated amino-terminal polystyrene (dPS-NH2) with anhydrideterminal poly(methyl methacrylate) (PMMA-anh) at a PS/PMMA interface has been observed with forward recoil spectrometry (FRES). Bilayer samples were constructed by placing thin films of PS containing ∼8.5 wt % dPS-NH2 on a PMMA-anh layer. Significant reaction was observed only after annealing the samples at 174°C for several hours, a time scale at least two orders of magnitude greater than the time required for the dPS-NH2 chains to diffuse through the bulk PS layer. The topography of the interfacial region as copolymer formed was measured using atomic force microscopy (AFM). Roughening of the PS/PMMA interface was observed to varying degrees in all annealed samples. Furthermore, the extent of this roughening was found to depend on the PS matrix molecular weight. Reaction in the samples with a high molecular weight PS matrix resulted in a root mean square roughness approximately equal to the radius of gyration Rg of the copolymer. However, approximately twice as much roughening was observed in the low molecular weight PS matrix. This study reveals how the molecular weight of one of the phases can affect the rate of reaction at a polymer/polymer interface.

Field-Effect Mobility and Morphology Study in Amorphous Films of Symmetric and Unsymmetrical Spiro-Linked Compounds

2002 ◽  
Vol 725 ◽  
Author(s):  
Tobat P. I. Saragi ◽  
Robert Pudzich ◽  
Thomas Fuhrmann ◽  
Josef Salbeck
Keyword(s):  
Field Effect ◽  
Smooth Surface ◽  
Amorphous Materials ◽  
Low Molecular Weight ◽  
Field Effect Mobility ◽  
Amorphous Films ◽  
Force Microscopy ◽  
Atomic Force ◽  
Saturation Region ◽  
Microscopy Images

AbstractWe have investigated the field-effect mobility of three kinds of low molecular weight spirolinked compounds, namely 2,2',7,7'-tetrakis (diphenylamino)-9,9'-spirobifluorene (spiro-TAD), 2,2',7,7'-tetrakis(biphenyl-4-yl)-9,9'-spirobifluorene (spiro-6φ) and 2,7-bis-(N,N-diphenylamino)- 2',7'-bis-(biphenyl-4-yl)-9,9'-spirobifluorene (spiro-X2). The field-effect mobilities of these materials in the saturation region are 8 x 10-4 cm2V-1s-1, 5 x 10-5 cm2V-1s-1 and 4 x 10-4 cm2V-1s-1 respectively. The atomic force microscopy images show that films prepared from these materials are amorphous with a very smooth surface and the limited field-effect mobility is due to the intrinsic behaviour of amorphous materials.

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.

Structural Characteristics and Ferroelectric Properties of Bismuth-Based Compound Thin Films Crystallized by Hot Isostatic Pressing

2009 ◽  
Vol 421-422 ◽  
pp. 143-147
Author(s):  
Masafumi Kobune ◽  
Hideto Tada ◽  
Hisashi Oshima ◽  
Daisuke Horii ◽  
Akihiro Tamura ◽  
...  
Keyword(s):  
Structural Characteristics ◽  
Ferroelectric Properties ◽  
Hot Isostatic Pressing ◽  
Film Surface ◽  
Secondary Phase ◽  
Gas Pressure ◽  
Root Mean Square Roughness ◽  
Isostatic Pressing ◽  
Force Microscopy ◽  
Atomic Force

After depositing amorphous (Bi0.5La0.5)(Ni0.5Ti0.5)O3 (BLNT) films on BLNT seed layer/Pt(100)/ MgO(100) substrates by room-temperature sputtering, the crystallization of the perovskite-struc- tured films has been tried by hot isostatic pressing (HIP). The samples with a single-phase perovskite structure HIP-treated at 800°C for 1 h under gas pressures of 0.51.0 MPa showed good crystallinity of  = 0.960.98 without accompanying the precipitation of the secondary phase. It was confirmed that a large root mean square roughness value of 44.2 nm for the sample HIP-treated at 800°C for 1 h under gas pressure of 0.1 MPa is due to innumerable Bi4Ti3O12-like rod-shaped grains precipitated in the film surface, based on atomic force microscopy. It is shown that the BLNT sample HIP-treated at 800°C for 1 h under gas pressure of 1.0 MPa exhibits the best hysteresis loop shape with a remanent polarization of Pr = 5 C/cm2 and a coercive field of Ec = 150 kV/cm of the six.

scholarly journals Дифракционные решетки с блеском, получаемые на пластинах Si --- первые результаты

2021 ◽  
Vol 91 (10) ◽  
pp. 1538
Author(s):  
Л.И. Горай ◽  
Т.Н. Березовская ◽  
Д.В. Мохов ◽  
В.А. Шаров ◽  
К.Ю. Шубина ◽  
...  
Keyword(s):  
Extreme Ultraviolet ◽  
Root Mean Square Roughness ◽  
Force Microscopy ◽  
Laser Lithography ◽  
Atomic Force ◽  
Groove Profile ◽  
Direct Laser ◽  
Triangular Profile ◽  
Extreme Ultraviolet Radiation ◽  
Protective Mask

Using direct laser lithography and liquid etching of polished vicinal Si(111) wafers, a technology was developed and diffraction gratings 500 /mm with a blaze angle of 4° were fabricated. The manufacturing process of a reflective Si-grating of a triangular profile (sawtooth) can be divided into four main steps: (1) obtaining a pattern of a protective mask for etching grooves; (2) anisotropic etching of grooves in KOH solution; (3) etching to smooth the grating profile and polish the surface of working facets; (4) coating to increase reflectivity. The samples obtained were characterized using scanning electron microscopy and atomic force microscopy methods to determine the shape of the groove profile and roughness: the shape turned out to be close to the ideal triangular, and the root-mean square roughness was less than 0.3 nm. With the help of the PCGrate™ code, taking into account the measured real groove profile, the diffraction efficiency of gratings operating in classical and conical mounts in soft-X-ray and extreme ultraviolet radiation has been simulated. The obtained efficiency values are close to the record ones for the corresponding spectral range and the Au-coating of the grating.

STRUCTURE AND OPTICAL PROPERTIES OF InN THIN FILM GROWN ON SiC BY REACTIVE RF MAGNETRON SPUTTERING

2013 ◽  
Vol 20 (01) ◽  
pp. 1350008 ◽  
Author(s):  
M. AMIRHOSEINY ◽  
Z. HASSAN ◽  
S. S. NG ◽  
G. ALAHYARIZADEH
Keyword(s):  
Thin Film ◽  
Optical Properties ◽  
Magnetron Sputtering ◽  
Rf Magnetron Sputtering ◽  
Root Mean Square Roughness ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Growth Orientation ◽  
Atomic Force

The structure and optical properties of InN thin film grown on 6H-SiC by reactive radio frequency magnetron sputtering were investigated. X-ray diffraction measurement shows that the deposited InN film has (101) preferred growth orientation and wurtzite structure. Atomic force microscopy results reveal smooth surface with root-mean-square roughness around 3.3 nm. One Raman-active optical phonon of E2(high) and two Raman- and infrared-active modes of A1(LO) and E1(TO) of the wurtzite InN are clearly observed at 488.7, 582.7 and 486 cm-1, respectively. These results leading to conclude that the wurtzite InN thin film with (101) preferred growth orientation was successfully grown on 6H-SiC substrate.

Nano-scale Observation of Si Trench Sidewall Surface Morphology by AFM Technology

2007 ◽  
Vol 1025 ◽  
Author(s):  
Reiko Hiruta ◽  
Hitoshi Kuribayashi ◽  
Ryosuke Shimizu
Keyword(s):  
Cross Sections ◽  
Longitudinal Direction ◽  
Signal To Noise ◽  
Force Microscopy ◽  
Nano Scale ◽  
Atomic Force ◽  
The Difference ◽  
A New Technique ◽  
Afm Observation ◽  
Sidewall Surface

AbstractWe have developed an atomic force microscopy (AFM) observation technique with which Si trench sidewall surface can be scanned with the tip of cantilever to investigate its nano-scale morphologies. By developing a new technique of cleaving the substrate at the center of a micron-sized trench along its longitudinal direction [011], the sidewall nano-scale morphology of the trench could be observed with the AFM technique. By comparing of cross sections of the images, we also investigated the difference between Si and carbon nanotube (CNT) tips for the AFM observations. According to the results, the CNT tip proved to show a superior signal-to-noise (S/N) ratio compared with the Si tip. The CNT tip enables us to observe the step patterns of the sidewalls of micron-sized trench structures in the various phases of hydrogen annealing.

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