The Impact of Pregrowth Conditions and Substrate Polytype on SiC Epitaxial Layer Morphology

1996 ◽  
Vol 423 ◽  
Author(s):  
A. A. Burk ◽  
L. B. Rowland ◽  
G. Augustine ◽  
H. M. Hobgood ◽  
R. H. Hopkins
Keyword(s):  
Epitaxial Layer ◽  
Substrate Surface ◽  
Surface Preparation ◽  
Growth Conditions ◽  
Epitaxial Layers ◽  
Axis Orientation ◽  
Step Flow ◽  
Morphological Defects ◽  
Step Flow Growth ◽  
The Impact

Abstract4H and 6H-SiC epitaxial layers exhibit characteristic morphological defects caused by process and substrate interferences with the a-axis directed step-flow growth. 4H-SiC is shown to typically exhibit worse morphology than 6H-SiC for a given off-axis orientation. SiC epitaxial layer defects are significantly reduced by the optimization of growth conditions and substrate surface preparation. The remaining highly variable defects are shown to emanate from the substrate surface with densities of ≥1000 cm−2

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.

Growth Mode and Defects in Aluminum Nitride Sublimated on (0001) 6H-SiC Substrates

2000 ◽  
Vol 639 ◽  
Author(s):  
Lianghong Liu ◽  
Bei Liu ◽  
Ying Shi ◽  
J. H. Edgar
Keyword(s):  
Substrate Surface ◽  
Surface Preparation ◽  
Growth Mode ◽  
Island Growth ◽  
Substrate Preparation ◽  
Step Flow ◽  
Long Time ◽  
Step Flow Growth ◽  
Sublimation Growth ◽  
Thermal Expansion Coefficient Mismatch

ABSTRACTThe effect of substrate preparation on the sublimation growth of AlN on 6H-SiC was investigated at about 1800°C and 400 torr. Short and long-time sublimation growths of AlN indicated that the nucleation, growth mode, and defects formed depended on the substrate surface preparation. Growth on an off-axis 6H-SiC substrate with 6H-SiC epilayer was in the step flow growth mode in contrast to the island growth mode on as-received substrates, while the 2-D growth was achieved on substrates first coated with an AlN epitaxial layer. Cracks due to the lattice and mainly large thermal expansion coefficient mismatch were always observed in the deposited AlN crystal, as characterized by SEM and optical microscopy.

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.

Point Contact Current Voltage Measurements of 4H-SiC Samples with Different Doping Profiles

2017 ◽  
Vol 897 ◽  
pp. 287-290 ◽  
Author(s):  
Matthias Kocher ◽  
Michael Niebauer ◽  
Mathias Rommel ◽  
Volker Haeublein ◽  
Anton J. Bauer
Keyword(s):  
Epitaxial Layer ◽  
Depth Profile ◽  
Point Contact ◽  
Surface Preparation ◽  
Epitaxial Layers ◽  
Depth Profiles ◽  
Current Voltage ◽  
Measured Resistance ◽  
Doping Profiles ◽  
Good Agreement

Point contact current voltage (PCIV) measurements were performed on 4H-SiC samples, both for n- an p-doped epitaxial layers as well as samples with rather shallow doping profiles realized by N- or Al-implantation in a range from 1016 cm-3 to 1019 cm-3. Surface preparation and measurement parameters were investigated in order to determine their influence on the measured resistance profiles. Furthermore depth profile measurements were performed on both an epitaxial layer as well as on implanted samples. These depth profiles could be measured reproducibly and showed good agreement with expected profiles for Al-implanted samples as well as for epitaxial layer whereas for N-implanted samples deviations between measured and expected profiles could be observed. It could be proven that PCIV profiling technique is a promising method for characterizing doped profiles in 4H-SiC, especially on Al-implanted samples.

Effects of substrate surface preparation on chemical vapor deposition growth of 4H-SiC epitaxial layers

2001 ◽  
Vol 30 (3) ◽  
pp. 228-234 ◽  
Author(s):  
S. E. Saddow ◽  
T. E. Schattner ◽  
J. Brown ◽  
L. Grazulis ◽  
K. Mahalingam ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Substrate Surface ◽  
Surface Preparation ◽  
Chemical Vapor ◽  
Epitaxial Layers ◽  
Chemical Vapor Deposition Growth

On the Formation of Intrinsic Defects in 4H-SiC by High Temperature Annealing Steps

2012 ◽  
Vol 717-720 ◽  
pp. 247-250 ◽  
Author(s):  
Bernd Zippelius ◽  
Jun Suda ◽  
Tsunenobu Kimoto
Keyword(s):  
High Temperature ◽  
Carrier Lifetime ◽  
Growth Conditions ◽  
Device Fabrication ◽  
Defect Concentration ◽  
Epitaxial Layers ◽  
High Temperature Annealing ◽  
Intrinsic Defects ◽  
Initial Defect ◽  
The Impact

In this paper the impact of high temperature annealing on the formation of intrinsic defects in 4H-SiC such as Z1/2 and EH6/7 was examined. Therefore, three epitaxial layers with various initial concentrations of the Z1/2- and EH6/7-centers (1011 – 1013 cm-3) were investigated. It turns out that depending on the initial defect concentration the high temperature annealing leads to a monotone increase of the Z1/2- and EH6/7-concentration in a temperature range from 1600 to 1750°C. For a defined temperature above these values, the resulting defect concentration is independent of the sample’s initial values. Beside the growth conditions themselves such as C/Si ratio the thermal post-growth processing has a severe impact on the carrier lifetime which must be taken into account during device fabrication.

scholarly journals Step bunching during Si(001) homoepitaxy caused by the surface diffusion anisotropy

2002 ◽  
Vol 749 ◽  
Author(s):  
J. Mysliveček ◽  
C. Schelling ◽  
F. Schäffler ◽  
G. Springholz ◽  
P. Šmilauer ◽  
...  
Keyword(s):  
Kinetic Monte Carlo ◽  
Monte Carlo Model ◽  
Growth Conditions ◽  
Scanning Tunneling ◽  
Diffusion Anisotropy ◽  
Island Growth ◽  
Tunneling Microscopy ◽  
Step Bunching ◽  
Step Flow ◽  
Step Flow Growth

ABSTRACTScanning tunneling microscopy experiments show that the unstable growth morphology observed during molecular beam homoepitaxy on slightly vicinal Si(001) surfaces consists of straight step bunches. The instability occurs under step-flow growth conditions and vanishes both during low-temperature island growth and at high temperatures. An instability with the same characteristics is observed in a 2D Kinetic Monte Carlo model of growth with incorporated Si(001)-like diffusion anisotropy. This provides strong evidence that the diffusion anisotropy destabilizes growth on Si(001) and similar surfaces towards step bunching. This new instability mechanism is operational without any additional step edge barriers.

MODELING OF THIN FILM GROWTH ON A TILTED MISCUT SUBSTRATE: STATISTICAL PROPERTIES AND THE OPTIMUM GROWTH CONDITIONS

2012 ◽  
Vol 26 (15) ◽  
pp. 1250087 ◽  
Author(s):  
PATCHA CHATRAPHORN ◽  
CHANAKAN CHOMNGAM
Keyword(s):  
Thin Film ◽  
Diffusion Length ◽  
Film Growth ◽  
Growth Conditions ◽  
Thin Film Growth ◽  
Vicinal Surface ◽  
Optimum Conditions ◽  
Step Flow ◽  
Step Flow Growth ◽  
Miscut Substrate

Most studies of thin film growth simulations are performed on flat substrates. However, in reality, a substrate is usually miscut leading to a vicinal surface with a small tilt. The goal of this work is to study effects of an initial configuration of a miscut substrate on the grown film. The Das Sarma–Tamborenea model with modified diffusion rules is used for the simulations. The modification is done to allow variation in the surface diffusion length and mobility of adatoms. The results show that the optimum conditions that lead to step-flow growth are long diffusion length and small step height.

Investigation of In-Grown Dislocations in 4H-SiC Epitaxial Layers

2006 ◽  
Vol 527-529 ◽  
pp. 147-152 ◽  
Author(s):  
Kazutoshi Kojima ◽  
Tomohisa Kato ◽  
Satoshi Kuroda ◽  
Hajime Okumura ◽  
Kazuo Arai
Keyword(s):  
Epitaxial Growth ◽  
Epitaxial Layer ◽  
Basal Plane ◽  
Growth Conditions ◽  
Epitaxial Layers ◽  
Etch Pit Density ◽  
High Conversion Efficiency ◽  
Etch Pit ◽  
Edge Dislocations

We have investigated the generation of new dislocations during the epitaxial growth of 4H-SiC layers. Dislocations were mainly propagated from the substrate into the epitaxial layer. However, it was found that some amount of new threading edge dislocations (TEDs) and basal plane dislocations (BPDs) were generated during the epitaxial growth. The generation of those dislocations appeared to depend on the in-situ H2 etching conditions, not the epitaxial growth conditions. By optimizing in-situ H2 etching condition, we were able to effectively suppress the generation of new dislocations during epitaxial growth, and obtain 4H-SiC epitaxial layers which have the equivalent etch pit density (EPD) to the substrates. Our additional investigation of the conversion of BPDs to TEDs revealed that its efficiency similarly depends on in-situ H2 etching. We were able to obtain a high conversion efficiency of 97 % by optimizing the in-situ H2 etching conditions before epitaxial growth.

Comparative Study of Defects in 4H-SiC Epilayers Grown on 4o Off-Axis (0001) and (000-1) Substrates

2014 ◽  
Vol 778-780 ◽  
pp. 143-146
Author(s):  
Takashi Aigo ◽  
Wataru Itoh ◽  
Tatsuo Fujimoto ◽  
Takayuki Yano
Keyword(s):  
Raman Spectroscopy ◽  
Epitaxial Growth ◽  
Growth Temperature ◽  
Stacking Faults ◽  
Step Flow ◽  
Micro Raman Spectroscopy ◽  
Imaging Observation ◽  
The Face ◽  
Morphological Defects ◽  
Step Flow Growth

In this paper, we present a comparison of defects in 4H-SiC epilayers grown on 4o off-axis (0001) and (000-1) substrates. It was confirmed using high sensitive surface observation and micro-Raman spectroscopy that the generation of epitaxial defects on (000-1) C-face substrates was less susceptible to substrate morphological defects such as pits than that on (0001) Si-face substrates and 'comet-like' defects on (000-1) C-faces were caused by the inclusion of 3C-SiC. Moreover, PL imaging observation showed that stacking fault densities decreased when increasing the growth temperature, and they increased when increasing the C/Si ratio, irrespective of the face polarity. The densities, however, were lower for C-faces at higher growth temperature and C/Si ratio. The present results indicated that C-faces were preferable to Si-faces to achieve smooth step-flow growth suppressing epitaxial defects and stacking faults, which were influenced by the substrate morphological defects and the fluctuation of C/Si ratio in the epitaxial growth.

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