Thermal Conductivity of Si/SiGe Superlattice Film

2008 ◽  
Author(s):  
Chun-Kai Liu ◽  
Heng-Chieh Chien ◽  
Ming-Ji Dai ◽  
Chih-Kuang Yu ◽  
Chun-Yeh Hsu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Theoretical Analysis ◽  
High Vacuum ◽  
Experimental Studies ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Interfacial Thermal Resistance ◽  
Boltzmann Transport ◽  
Superlattice Structure ◽  
Acoustic Mismatch

It has been proposed that the use of superlattice structure is effective for reduction of lattice thermal conductivity in the direction perpendicular to superlattice interfaces which can lead to improvement of figure of merit. In this work, we have evaluated the thermal conductivity of Si/SiGe superlattice structure films by theoretical analysis and experimental studies. In experiments, the ultra-high vacuum chemical vapor deposition (UHVCVD) has been employed to formation the Si/Si0.71Ge0.29 superlattice film. The cross-plane thermal conductivity of a Si/Si0.71Ge0.29 superlattice is measured based on the 3 ω method. In theoretical analysis, we use the Boltzmann transport equation to analyze the phenon transport in superlattice film. We compared the thermal conductivities of several Si/Si0.71Ge0.29 superlattice structure films by changing the thickness of Si and Si0.71Ge0.29. The results indicate that increasing the period (one layer Si and one layer Si0.71Ge0.29) length will lead to increase acoustic mismatch between the adjacent layers, and hence increased interfacial thermal resistance. However, if the total thickness of the superlattice film is fixed, reducing the period length will lead to decreased effective thermal conductivity due to the increased number of interfaces.

Temperature Dependent Thermal Conductivity of Symmetrically Strained Si/Ge Superlattices

1999 ◽  
Author(s):  
Theodorian Borca-Tasciuc ◽  
Jianlin Liu ◽  
Taofang Zeng ◽  
Weili Liu ◽  
David W. Song ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Growth Temperature ◽  
Temperature Drop ◽  
Experimental Studies ◽  
Chemical Vapor ◽  
Temperature Dependent ◽  
Strained Si ◽  
Superlattice Structure ◽  
Temperature Dependent Thermal Conductivity ◽  
Measured Thermal Conductivity

Abstract Experimental evidence for a significant thermal conductivity reduction has been reported in recent years for GaAs/AlAs, Si/Ge, and Bi2Te3/Sb2Te3 superlattices. Previously reported experimental studies on Si/Ge superlattices are based on samples grown by metal oxide chemical vapor deposition (MOCVD) on GaAs substrates with Ge buffers. In this work, we present experimental results on the temperature dependent thermal conductivity of symmetrically strained Si/Ge superlattices grown by molecular beam epitaxy (MBE) as a function of the superlattice period and the growth temperature. Thermal conductivity measurements are performed using a differential 3ω method. In this technique, the temperature drop across the superlattice film is experimentally determined and used to estimate the thermal conductivity of the film. Transmission electron microscopy (TEM) is employed to study the quality of the superlattice and the influence of the growth temperature on the superlattice structure. For all the superlattices studied, the measured thermal conductivity values are lower than that of the Si0.5Ge0.5 alloy. Furthermore, the measured thermal conductivity of a 40Å period Si/Ge superlattice with high dislocation density is comparable to the calculated minimum thermal conductivity of the constituent bulk materials.

Challenge to 200 mm 3C-SiC Wafers Using SOI

2005 ◽  
Vol 483-485 ◽  
pp. 205-208 ◽  
Author(s):  
Motoi Nakao ◽  
Hirofumi Iikawa ◽  
Katsutoshi Izumi ◽  
Takashi Yokoyama ◽  
Sumio Kobayashi
Keyword(s):  
Cross Section ◽  
Vapor Deposition ◽  
Seed Layer ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Average Thickness ◽  
Entire Region ◽  
Transmission Electron ◽  
Good Crystallinity

200 mm wafer with 3C-SiC/SiO2/Si structure has been fabricated using 200 mm siliconon- insulator (SOI) wafer. A top Si layer of 200 mm SOI wafer was thinned down to approximately 5 nm by sacrificial oxidization, and the ultrathin top Si layer was metamorphosed into a 3C-SiC seed layer using a carbonization process. Afterward, an epitaxial SiC layer was grown on the SiC seed layer with ultra-high vacuum chemical vapor deposition. A cross-section transmission electron microscope indicated that a 3C-SiC seed layer was formed directly on the buried oxide layer of 200 mm wafer. The epitaxial SiC layer with an average thickness of approximately 100 nm on the seed was recognized over the entire region of the wafer, although thickness uniformity of the epitaxial SiC layer was not as good as that of SiC seed layer. A transmission electron diffraction image of the epitaxial SiC layer showed a monocrystalline 3C-SiC(100) layer with good crystallinity. These results indicate that our method enables to realize 200 mm SiC wafers.

Ultra-high vacuum chemical vapor deposition and in situ characterization of titanium oxide thin films

1991 ◽  
Vol 6 (9) ◽  
pp. 1913-1918 ◽  
Author(s):  
Jiong-Ping Lu ◽  
Rishi Raj
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Titanium Oxide ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Titanium Isopropoxide ◽  
Ultra High Vacuum

Chemical vapor deposition (CVD) of titanium oxide films has been performed for the first time under ultra-high vacuum (UHV) conditions. The films were deposited through the pyrolysis reaction of titanium isopropoxide, Ti(OPri)4, and in situ characterized by x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). A small amount of C incorporation was observed during the initial stages of deposition, through the interaction of precursor molecules with the bare Si substrate. Subsequent deposition produces pure and stoichiometric TiO2 films. Si–O bond formation was detected in the film-substrate interface. Deposition rate was found to increase with the substrate temperature. Ultra-high vacuum chemical vapor deposition (UHV-CVD) is especially useful to study the initial stages of the CVD processes, to prepare ultra-thin films, and to investigate the composition of deposited films without the interference from ambient impurities.

Homoepitaxy of Ge on ozone-treated Ge (1 0 0) substrate by ultra-high vacuum chemical vapor deposition

2019 ◽  
Vol 507 ◽  
pp. 113-117 ◽  
Author(s):  
Jiaqi Wang ◽  
Limeng Shen ◽  
Guangyang Lin ◽  
Jianyuan Wang ◽  
Jianfang Xu ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum

Carbon Incorporation in Gaas grown by UHVCVD Using Trimethylgallium and Arsine

1992 ◽  
Vol 281 ◽  
Author(s):  
Seong-Ju Park ◽  
Jeong-Rae Ro ◽  
Jae-Ki Sim ◽  
El-Hang Lee
Keyword(s):  
Growth Rates ◽  
Hole Concentration ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Chemical Beam Epitaxy ◽  
Hydrogen Atoms ◽  
Carbon Incorporation ◽  
Significant Drop ◽  
P Type

ABSTRACTWe present results of a study on the effect of unprecracked arsine(AsH3) and trimethylgallium(TMGa) on carbon incorporation in UHVCVD(Ultra High Vacuum Chemical Vapor Deposition) grown GaAs epilayers on GaAs(100). Three distinct temperature-dependent regions of growth rates were identified as growth temperature was increased from 570 to 690°C. The growth rates were also strongly dependent on V/III ratio in a range of 5 to 30, which clearly indicates that the growth rate is determined by the amount of arsenic adsorbed on the surface at low V/III ratio and adsorption of TMGa or decomposition process at high V/III ratio. Hall concentration measurements and low temperature photoluminescence data show that the films are all p-type and their impurity concentrations are reduced by two orders of magnitude compared to those of epilayers grown by CBE(Chemical Beam Epitaxy) which employs TMGa and arsenic(precracked arsines) as source materials. Our results indicate that the hydrogen atoms dissociated from adsorbed arsine may remove hydrocarbon species resulting in a significant drop in hole concentration.

Water Desorption from Magnesium Oxide Films Fabricated by Chemical Vapor Deposition

2006 ◽  
Vol 11-12 ◽  
pp. 693-696 ◽  
Author(s):  
S. Kawaguchi ◽  
K.C. Namiki ◽  
S. Ohshio ◽  
Junichi Nishino ◽  
H. Saitoh
Keyword(s):  
Chemical Vapor Deposition ◽  
Magnesium Oxide ◽  
Vapor Deposition ◽  
High Vacuum ◽  
Secondary Electron Emission ◽  
Film Surface ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Water Desorption ◽  
Plasma Sputtering

Magnesium oxide (MgO) films are utilized for the anti-plasma sputtering coating with excellent ability of secondary electron emission in plasma display panels (PDP). These properties are degraded by the impurities adsorbed on the film surface. Therefore, we should obtain impurity-free surface during the PDP manufacturing process. We have synthesized whisker and continuous film types of metal oxide using a chemical vapor deposition (CVD) method operated under atmosphere. In this study, a temperature programmed desorption method has been applied to detect residual species adsorbed on the surface of the present films in the ultra-high vacuum atmosphere. The amount of water adsorption was determined by this method.

scholarly journals Interwell coupling effect in Si/SiGe quantum wells grown by ultra high vacuum chemical vapor deposition

2007 ◽  
Vol 2 (3) ◽  
pp. 149-154
Author(s):  
Rui Wang ◽  
Soon Fatt Yoon ◽  
Fen Lu ◽  
Wei Jun Fan ◽  
Chong Yang Liu ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Quantum Wells ◽  
Vapor Deposition ◽  
Coupling Effect ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Sige Quantum Wells
Sign in / Sign up

Export Citation Format

Share Document