Surface Morphology and Composition Characterization at the Initial Stages of AlN Crystal Growth

2000 ◽  
Vol 639 ◽  
Author(s):  
B. Liu ◽  
Y. Shi ◽  
L. Liu ◽  
J.H. Edgar ◽  
D.N. Braski
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Silicon Nitride ◽  
Chemical Composition ◽  
Surface Morphology ◽  
Stages Of Growth ◽  
Initial Stage ◽  
Bare Substrate

ABSTRACTThe morphology and composition of AlN crystals on 6H-SiC (0001) at the initial stage of crystal growth by sublimation re-condensation technique were investigated by SEM and SAM. Discontinuous AlN coverage occurred after 15 minutes growth. The AlN nuclei size, and growth rate increased as temperature increased or pressure decreased. The SiC substrate decomposed leaving hexagonal hillocks; simultaneously, the AlN nucleated on these SiC hillocks apparently rotated by 15° to 30°. The chemical composition of the substrate and different AlN crystal facets were characterized by SAM. The bare substrate area was stoichiometric SiC with insignificant conversion to silicon nitride, while Si and C preferentially incorporated in the AlN at the initial stages of growth on specific crystal planes.

Effect of Additional HCl on the Surface Morphology of High Quality GaN on Sapphire by HVPE

2001 ◽  
Vol 693 ◽  
Author(s):  
X.Q. Xiu ◽  
R. Zhang ◽  
D.Q. Lu ◽  
L. Gu ◽  
B. Shen ◽  
...  
Keyword(s):  
Growth Rate ◽  
Surface Morphology ◽  
Smooth Surface ◽  
Growth Front ◽  
Hydride Vapor Phase Epitaxy ◽  
Nucleation Density ◽  
High Quality ◽  
Lower Growth ◽  
Initial Stage ◽  
Lower Growth Rate

AbstractThe effect of introduction of additional HCl on the surface morphology and structural properties of hydride vapor phase epitaxy grown GaN during growth is investigated, and high quality GaN with smooth surface on sapphire is obtained by adding the additional HCl into the HVPE reactor. The result is attributed to the control of polarity of GaN films during growth. The additional HCl altered the equilibrium at the GaN growth front, and the reversible reaction decreased the nucleation density or growth rate. Further, lower growth rate promote the surface diffusion and the coalescence over (0001) plane. Additional HCl may improve the surface morphology by suppressing the (000-1) polarity growth in the initial stage of the growth.

scholarly journals Analytical solutions of the segregation problem

2018 ◽  
Vol 194 ◽  
pp. 01045
Author(s):  
Andrey A. Pil'nik ◽  
Andrey A. Chernov
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Analytical Solutions ◽  
Heat Removal ◽  
Normal Growth ◽  
Crystal Growth Rate ◽  
Dissolved Gas ◽  
Initial Stage ◽  
Self Similar Solution ◽  
Growth Problem

New analytical solutions of the segregation problem were found. The segregation is caused by the dissolved gas displacement by a moving crystallization front. The displacement is caused by the low solubility of the volatiles in solid, so the dissolved gas is withdrawn from the crystallizing melt towards the surrounding melt. Two different modes of crystallization were considered. The first one is the case of constant crystal growth rate which takes place in the case of intensive heat removal or when only initial stage of crystallization process is considered. The second mode is the “normal growth law” which is a self-similar solution of the crystal growth problem. In this case the crystal growth rate is inversely proportional to a square root of time. In contrast to the already existing solutions here the solidification shrinkage is taken into account.

Photo-Assisted Molecular Layer Epitaxy

1987 ◽  
Vol 101 ◽  
Author(s):  
Jun-Ichi Nishizava ◽  
Toru KurabayashI
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Surface Morphology ◽  
Epitaxial Film ◽  
Molecular Layer ◽  
Wavelength Dependence ◽  
Epitaxial Films ◽  
Time Duration ◽  
Induced Reaction

ABSTRACTPhotoexcitation effects of GaAs vapor phase epitaxy have been studied. The growth rate is enhanced by irradiating the substrate zone with an exciier laser irradiation at 2 4 9 n m wavelength, however, the growth rate is reduced by irradiating the source Ga zone with a 249 or 222m exciier laser at températures below 650*C. Because of sharp wavelength dependence and from the result of the theoretical estimations, these effects have been concluded to be caused not by a therma1 -induced reaction but, rather, by photoinduced reactions.Influence of photoexcitation of the film grown by molecular layer epitaxy has been also studied. Photoirradiation could be independently undertaken at different crystal growth steps, e.g. the irradiation duration could be synchronized with the time duration of each gases supply and exhaust. By this method “synchronized irradiation”, the quality of the epitaxial film and the surface morphology of epitaxial films grown by molecular layer epitaxy were improved.

TEMPERATURE DEPENDENCE OF THE CRYSTAL GROWTH RATE IN POLAR GLACIERS

1987 ◽  
Vol 48 (C1) ◽  
pp. C1-661-C1-662 ◽  
Author(s):  
J. R. PETIT ◽  
P. DUVAL ◽  
C. LORIUS
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Temperature Dependence ◽  
Crystal Growth Rate

ФОРМИРОВАНИЕ ПЕРЕХОДНОГО СЛОЯ ALN НА ТЕМПЛЕЙТАХ 3С-SIC/SI(111) МЕТОДОМ АММИАЧНОЙ МОЛЕКУЛЯРНО-ЛУЧЕВОЙ ЭПИТАКСИИ

2020 ◽  
Vol 96 (3s) ◽  
pp. 148-153
Author(s):  
С.Д. Федотов ◽  
А.В. Бабаев ◽  
В.Н. Стаценко ◽  
К.А. Царик ◽  
В.К. Неволин
Keyword(s):  
Crystal Structure ◽  
Growth Rate ◽  
Low Temperature ◽  
Surface Morphology ◽  
Single Crystal ◽  
Root Mean Square Roughness ◽  
Rate Variation ◽  
Mean Square ◽  
Nucleation Layer ◽  
Low Temperature Epitaxy

Представлены результаты изучения морфологии поверхности и структуры слоев AlN, сформированных аммиачной МЛЭ на темплейтах 3C-SiC/Si(111) on-axis- и 4° off-axis-разориентации. Опробован технологический режим низкотемпературной эпитаксии зародышевого слоя AlN на поверхности 3C-SiC(111). Среднеквадратичная шероховатость поверхности (5 х 5 мкм) слоев AlN толщиной 150 ± 50 нм составила 2,5-3,5 нм на темплейтах 3C-SiC/Si(111) on-axis и 3,3-3,5 нм на 4° off-axis. Показано уменьшение шероховатости смачивающего слоя AlN при изменении скорости роста. Получены монокристаллические слои AlN(0002) со значениями FWHM (ω-геометрия) 1,4-1,6°. The paper presents the surface morphology and crystal structure of AlN layers formed by ammonia MBE on 3C-SiC/Si(111) on-axis and 4° off-axis disorientation. It offers the technological approach of low-temperature epitaxy of the AlN nucleation layer on the 3C-SiC (111) surface. Root mean square roughness (5 х 5 |xm) of AlN layers with thickness of 150 ± 50 nm was 2,5-3,5 nm onto on-axis templates and 3.3-3.5 nm onto 4° off-axis. It appears that the RMS roughness of the AlN surface is changing with the growth rate variation. Single-crystal AlN(0002) layers with FWHM values (ω-geometry) of 1.4-1.6° have been obtained.

Comparison of copper sulphate pentahydrate growth rates determined by different methods

1990 ◽  
Vol 55 (7) ◽  
pp. 1691-1707 ◽  
Author(s):  
Miloslav Karel ◽  
Jiří Hostomský ◽  
Jaroslav Nývlt ◽  
Axel König
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Fluidized Bed ◽  
Growth Rates ◽  
Copper Sulphate ◽  
Crystal Growth Rate ◽  
Effect Of Temperature ◽  
Rotating Disc ◽  
Shape Factors ◽  
Data Treatment

Crystal growth rates of copper sulphate pentahydrate (CuSO4.5 H2O) determined by different authors and methods are compared. The methods included in this comparison are: (i) Measurement on a fixed crystal suspended in a streaming solution, (ii) measurement on a rotating disc, (iii) measurement in a fluidized bed, (iv) measurement in an agitated suspension. The comparison involves critical estimation of the supersaturation used in measurements, of shape factors used for data treatment and a correction for the effect of temperature. Conclusions are drawn for the choice of values to be specified when data of crystal growth rate measurements are published.

Effect of growth‐rate ratio on surface morphology of homoepitaxial diamond (100) and (111)

1996 ◽  
Vol 69 (26) ◽  
pp. 4032-4034 ◽  
Author(s):  
Robin E. Rawles ◽  
William G. Morris ◽  
Mark P. D’Evelyn
Keyword(s):  
Growth Rate ◽  
Surface Morphology ◽  
Rate Ratio
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