Sai Jiao - Academia.edu (original) (raw)
Papers by Sai Jiao
Parmi les polytypes les plus connus du carbure de silicium (SiC), le polytype cubique (3C-SiC), e... more Parmi les polytypes les plus connus du carbure de silicium (SiC), le polytype cubique (3C-SiC), est le seul qui peut croitre sur des substrats silicium. L’heterostructure 3C-SiC/Si est interessante non seulement pour son faible cout de production mais aussi pour la conception de Systemes Micro-Electro-Mecaniques (« MEMS »). La valeur elevee du module de Young du 3C-SiC, compare a celui du silicium, permettrait a des cantilevers submicroniques, fabriques a partir de films minces de 3C-SiC, de vibrer a ultra-hautes frequences (>100MHz). Cette haute frequence de resonance est la cle pour obtenir un systeme AFM non-contact ultra-sensible et rapide. Cependant, il n’existe pas de cantilever en SiC disponible sur le marche en raison de la difficulte a elaborer des films minces de 3C-SiC de bonne qualite, la technique de synthese la plus utilisee etant le Depot Chimique en phase Vapeur (CVD). La raison premiere de cette difficulte a obtenir un materiau de bonne qualite reside essentielle...
physica status solidi (a), 2016
Detailed analysis on the planar defects in rotated 3C-SiC() films grown on Si(110) substrates hav... more Detailed analysis on the planar defects in rotated 3C-SiC() films grown on Si(110) substrates have been conducted by using X-ray diffraction and cross-sectional transmission electron microscopy. While the film mostly consists of a rotated region, a portion was found in its nonrotated (3C-SiC(110)) configuration, forming domain boundaries in between. Inplane twins were also found to exist within both the rotated and nonrotated regions. Their origins and their impacts on the epitaxial graphene formation on the 3C-SiC film are discussed.
Diamond and Related Materials, 2016
Abstract Formation of epitaxial graphene (EG) on 3C–SiC films heteroepitaxially grown on Si subst... more Abstract Formation of epitaxial graphene (EG) on 3C–SiC films heteroepitaxially grown on Si substrates, otherwise known as graphene-on-silicon (GOS) technology, has a high potential in future nanocarbon-based electronics. The EG's quality in GOS however remains mediocre due mostly to the high density of crystal defects in the 3C–SiC/Si films caused by the large (~ 20%) lattice-mismatch between Si and 3C–SiC crystals. Resultant Si out-diffusion along the planar defects during the high-temperature (~ 1525 K) graphitization annealing can also account for the degradation. Here we propose a two-step growth technique that consists of seeding of rotated 3C-SiC(-1-1-1) crystallites on the Si(110) substrate, conducted in the high-temperature-low-pressure regime, followed by a rapid growth of SiC films in the low-temperature-high-pressure regime. We succeeded in forming an almost lattice-relaxed 3C-SiC(-1-1-1) film on Si(110), having a sufficient thickness (~ 200 nm) that we believe is able to suppress the Si out-diffusion during graphitization. A graphitization annealing applied to this epi-film yields an EG, whose domain size is increased by 60% as compared to that of conventional GOS films.
Materials Science Forum
The growth of graphene on 3C-SiC/Si heterostructure is a promising approach, which provides low p... more The growth of graphene on 3C-SiC/Si heterostructure is a promising approach, which provides low production cost, high scalability and easiness of nano-electro-mechanical system fabrication. However, the quality of graphene is still insufficient for device applications due to mediocre morphological and structural quality of the 3C-SiC epilayers compared to bulk SiC crystals and to excessive Si out-diffusion from the Si substrate. Here, we propose a solution of inserting a 4H-AlN layer between 3C-SiC and Si, which allows us to polish the 3C-SiC film without enhancement of the Si out-diffusion despite the thinning of the 3C-SiC. With this insertion, a considerable quality improvement is achieved in our graphene-on-silicon.
ABSTRACT The recent achievement of a continuous silicon monocrystalline thin film on 3C-SiC epila... more ABSTRACT The recent achievement of a continuous silicon monocrystalline thin film on 3C-SiC epilayers deposited on silicon substrates has opened the field for new microstructures. In this work, this original hetero-structure is the basis for the elaboration of an entire cantilever for atomic force microscopy. The hetero-epitaxially grown silicon layer is used to define the tip of the cantilever fabricated from the 3C-SiC epilayer deposited on silicon. The complete cantilever is elaborated by plasma etching using a nickel mask. The use of a full dry etching process is very promising as it is independent of the crystalline orientation of the silicon epilayer contrary to process based on wet etching solutions. Moreover, based on such hetero-structure, new MEMS devices can be considered.
Journal of Physics D: Applied Physics, 2014
By forming a thin 3C-SiC film on Si substrates and by annealing it at ∼1500 K in vacuo, few-layer... more By forming a thin 3C-SiC film on Si substrates and by annealing it at ∼1500 K in vacuo, few-layer graphene is formed epitaxially on Si substrates. In this graphene-on-silicon (GOS) technology, graphene grows at least on three major low-index Si surfaces: (1 1 1), (1 0 0) and (1 1 0), which allows tuning of structural and electronic properties of epitaxial graphene by simply controlling the crystallographic orientation of the surface. A typical example can be found in the two types of graphene formed on 3C-SiC(1 1 1) surfaces; the one on 3C-SiC(1 1 1)/Si(1 1 1) shows a Bernal stacking with an interfacial buffer layer, while the one on 3C-SiC(1 1 1)/Si(1 1 0) shows a non-Bernal stacking without an interfacial buffer layer. Inserting an AlN interlayer between Si and 3C-SiC significantly contributes to improvement of the GOS quality. Moreover, thanks to the sealing effect of the AlN layer against Si out-diffusion, we can apply chemomechanical polishing of SiC surface to reduce the surface roughness, which can further accentuate the effect of H 2 annealing of the surface. As a result, a D to G band intensity ratio as low as 0.4 is obtained.
Materials Science …, 2012
The growth of continuous silicon monocrystalline thin films on 3C-SiC epilayers deposited on sili... more The growth of continuous silicon monocrystalline thin films on 3C-SiC epilayers deposited on silicon substrates is presented in this study. Such heterostructures can be beneficial for the fabrication of Micro Electro Mechanical Systems or electronic ...
Materials Science …, 2012
A detailed experimental study of the mean and gradient stress, existing in the as-grown cubic sil... more A detailed experimental study of the mean and gradient stress, existing in the as-grown cubic silicon carbide epilayers, is presented in this paper.(100) and (111) oriented epiwafers with considerable film thickness variation have been elaborated using a ...
MRS …, 2010
X-Ray Diffraction was used to evaluate the crystalline quality of the epilayers. Scanning Electro... more X-Ray Diffraction was used to evaluate the crystalline quality of the epilayers. Scanning Electron Microscopy observations of static cantilever deflection highlight the major difference between the stress states of (100) and (111) oriented layers for which the intrinsic stresses are of ...
The value of the full width at half maximum of the rocking curve of symmetric 3C SiC reflection, ... more The value of the full width at half maximum of the rocking curve of symmetric 3C SiC reflection, often considered as the "quality indicator" of the epitaxial film, is in fact a convolution of several contributions, among which the curvature related part may play a dominant role. Thus, a precise determination of the curvature related broadening is necessary to extract the information on the film quality from the rocking curve. In this paper we demonstrate experimentally the coexistence of two independent curvature related broadening effects. We also propose an analytical model that describes quantitatively both effects
In this work we analyze the static behavior of cantilevers elaborated on the basis of 3C SiC thin... more In this work we analyze the static behavior of cantilevers elaborated on the basis of 3C SiC thin films grown by chemical vapor deposition on (100) and (111) oriented silicon substrates. A direct microscope observation of cantilever bending indicates the opposite sign of stress gradient (respectively negative and positive) for both film orientations. The correlation of this observation with the commonly admitted nature of intrinsic stress for each orientation (respectively compressive and tensile) leads us to an unexpected conclusion: instead of relaxing, the absolute value of the intrinsic stress increases from the interface to the layer surface. We propose an analytical model that could explain this phenomenon.
Parmi les polytypes les plus connus du carbure de silicium (SiC), le polytype cubique (3C-SiC), e... more Parmi les polytypes les plus connus du carbure de silicium (SiC), le polytype cubique (3C-SiC), est le seul qui peut croitre sur des substrats silicium. L’heterostructure 3C-SiC/Si est interessante non seulement pour son faible cout de production mais aussi pour la conception de Systemes Micro-Electro-Mecaniques (« MEMS »). La valeur elevee du module de Young du 3C-SiC, compare a celui du silicium, permettrait a des cantilevers submicroniques, fabriques a partir de films minces de 3C-SiC, de vibrer a ultra-hautes frequences (>100MHz). Cette haute frequence de resonance est la cle pour obtenir un systeme AFM non-contact ultra-sensible et rapide. Cependant, il n’existe pas de cantilever en SiC disponible sur le marche en raison de la difficulte a elaborer des films minces de 3C-SiC de bonne qualite, la technique de synthese la plus utilisee etant le Depot Chimique en phase Vapeur (CVD). La raison premiere de cette difficulte a obtenir un materiau de bonne qualite reside essentielle...
physica status solidi (a), 2016
Detailed analysis on the planar defects in rotated 3C-SiC() films grown on Si(110) substrates hav... more Detailed analysis on the planar defects in rotated 3C-SiC() films grown on Si(110) substrates have been conducted by using X-ray diffraction and cross-sectional transmission electron microscopy. While the film mostly consists of a rotated region, a portion was found in its nonrotated (3C-SiC(110)) configuration, forming domain boundaries in between. Inplane twins were also found to exist within both the rotated and nonrotated regions. Their origins and their impacts on the epitaxial graphene formation on the 3C-SiC film are discussed.
Diamond and Related Materials, 2016
Abstract Formation of epitaxial graphene (EG) on 3C–SiC films heteroepitaxially grown on Si subst... more Abstract Formation of epitaxial graphene (EG) on 3C–SiC films heteroepitaxially grown on Si substrates, otherwise known as graphene-on-silicon (GOS) technology, has a high potential in future nanocarbon-based electronics. The EG's quality in GOS however remains mediocre due mostly to the high density of crystal defects in the 3C–SiC/Si films caused by the large (~ 20%) lattice-mismatch between Si and 3C–SiC crystals. Resultant Si out-diffusion along the planar defects during the high-temperature (~ 1525 K) graphitization annealing can also account for the degradation. Here we propose a two-step growth technique that consists of seeding of rotated 3C-SiC(-1-1-1) crystallites on the Si(110) substrate, conducted in the high-temperature-low-pressure regime, followed by a rapid growth of SiC films in the low-temperature-high-pressure regime. We succeeded in forming an almost lattice-relaxed 3C-SiC(-1-1-1) film on Si(110), having a sufficient thickness (~ 200 nm) that we believe is able to suppress the Si out-diffusion during graphitization. A graphitization annealing applied to this epi-film yields an EG, whose domain size is increased by 60% as compared to that of conventional GOS films.
Materials Science Forum
The growth of graphene on 3C-SiC/Si heterostructure is a promising approach, which provides low p... more The growth of graphene on 3C-SiC/Si heterostructure is a promising approach, which provides low production cost, high scalability and easiness of nano-electro-mechanical system fabrication. However, the quality of graphene is still insufficient for device applications due to mediocre morphological and structural quality of the 3C-SiC epilayers compared to bulk SiC crystals and to excessive Si out-diffusion from the Si substrate. Here, we propose a solution of inserting a 4H-AlN layer between 3C-SiC and Si, which allows us to polish the 3C-SiC film without enhancement of the Si out-diffusion despite the thinning of the 3C-SiC. With this insertion, a considerable quality improvement is achieved in our graphene-on-silicon.
ABSTRACT The recent achievement of a continuous silicon monocrystalline thin film on 3C-SiC epila... more ABSTRACT The recent achievement of a continuous silicon monocrystalline thin film on 3C-SiC epilayers deposited on silicon substrates has opened the field for new microstructures. In this work, this original hetero-structure is the basis for the elaboration of an entire cantilever for atomic force microscopy. The hetero-epitaxially grown silicon layer is used to define the tip of the cantilever fabricated from the 3C-SiC epilayer deposited on silicon. The complete cantilever is elaborated by plasma etching using a nickel mask. The use of a full dry etching process is very promising as it is independent of the crystalline orientation of the silicon epilayer contrary to process based on wet etching solutions. Moreover, based on such hetero-structure, new MEMS devices can be considered.
Journal of Physics D: Applied Physics, 2014
By forming a thin 3C-SiC film on Si substrates and by annealing it at ∼1500 K in vacuo, few-layer... more By forming a thin 3C-SiC film on Si substrates and by annealing it at ∼1500 K in vacuo, few-layer graphene is formed epitaxially on Si substrates. In this graphene-on-silicon (GOS) technology, graphene grows at least on three major low-index Si surfaces: (1 1 1), (1 0 0) and (1 1 0), which allows tuning of structural and electronic properties of epitaxial graphene by simply controlling the crystallographic orientation of the surface. A typical example can be found in the two types of graphene formed on 3C-SiC(1 1 1) surfaces; the one on 3C-SiC(1 1 1)/Si(1 1 1) shows a Bernal stacking with an interfacial buffer layer, while the one on 3C-SiC(1 1 1)/Si(1 1 0) shows a non-Bernal stacking without an interfacial buffer layer. Inserting an AlN interlayer between Si and 3C-SiC significantly contributes to improvement of the GOS quality. Moreover, thanks to the sealing effect of the AlN layer against Si out-diffusion, we can apply chemomechanical polishing of SiC surface to reduce the surface roughness, which can further accentuate the effect of H 2 annealing of the surface. As a result, a D to G band intensity ratio as low as 0.4 is obtained.
Materials Science …, 2012
The growth of continuous silicon monocrystalline thin films on 3C-SiC epilayers deposited on sili... more The growth of continuous silicon monocrystalline thin films on 3C-SiC epilayers deposited on silicon substrates is presented in this study. Such heterostructures can be beneficial for the fabrication of Micro Electro Mechanical Systems or electronic ...
Materials Science …, 2012
A detailed experimental study of the mean and gradient stress, existing in the as-grown cubic sil... more A detailed experimental study of the mean and gradient stress, existing in the as-grown cubic silicon carbide epilayers, is presented in this paper.(100) and (111) oriented epiwafers with considerable film thickness variation have been elaborated using a ...
MRS …, 2010
X-Ray Diffraction was used to evaluate the crystalline quality of the epilayers. Scanning Electro... more X-Ray Diffraction was used to evaluate the crystalline quality of the epilayers. Scanning Electron Microscopy observations of static cantilever deflection highlight the major difference between the stress states of (100) and (111) oriented layers for which the intrinsic stresses are of ...
The value of the full width at half maximum of the rocking curve of symmetric 3C SiC reflection, ... more The value of the full width at half maximum of the rocking curve of symmetric 3C SiC reflection, often considered as the "quality indicator" of the epitaxial film, is in fact a convolution of several contributions, among which the curvature related part may play a dominant role. Thus, a precise determination of the curvature related broadening is necessary to extract the information on the film quality from the rocking curve. In this paper we demonstrate experimentally the coexistence of two independent curvature related broadening effects. We also propose an analytical model that describes quantitatively both effects
In this work we analyze the static behavior of cantilevers elaborated on the basis of 3C SiC thin... more In this work we analyze the static behavior of cantilevers elaborated on the basis of 3C SiC thin films grown by chemical vapor deposition on (100) and (111) oriented silicon substrates. A direct microscope observation of cantilever bending indicates the opposite sign of stress gradient (respectively negative and positive) for both film orientations. The correlation of this observation with the commonly admitted nature of intrinsic stress for each orientation (respectively compressive and tensile) leads us to an unexpected conclusion: instead of relaxing, the absolute value of the intrinsic stress increases from the interface to the layer surface. We propose an analytical model that could explain this phenomenon.