Low Temperature CVD SiC Coated Si Microcomponents for Reduced Scale Engines

Author(s):  
M. B. J. Wijesundara ◽  
D. C. Walther ◽  
C. R. Stoldt ◽  
K. Fu ◽  
D. Gao ◽  
...  

The unique operating conditions of micro-thermochemical systems introduce many materials compatibility issues that must be addressed, particularly where thin film coatings are concerned. These issues include oxidation, wear, friction, and thermal stability. This work aims to explore the effectiveness of polycrystalline 3C-SiC films deposited by low temperature chemical vapor deposition on silicon substrates as a means for the remediation of these effects. The chemical structure of the deposited films is examined by X-ray photoelectron spectroscopy and X-ray diffraction techniques. Surface physical characteristics are evaluated by atomic force microcopy as well as by scanning electron microscopy. The structural makeup of these films is characterized both optically and by the sample’s resistance to chemical etching. These barrier films are found to conformally deposit and can therefore be used to coat substrates or individual components, as well as to create highly environmentally resistant sensor elements. Samples are exposed to both a non-reactive flow high temperature source and reactive flow condition (H2–air flame) to determine their survivability. The SiC films are shown to possess a relatively high oxidation resistance when compared to Si.

2000 ◽  
Vol 611 ◽  
Author(s):  
Akira Izumi ◽  
Hidekazu Sato ◽  
Hideki Matsumura

ABSTRACTThis paper reports a procedure for low-temperature nitridation of silicon dioxide (SiO2) surfaces using species produced by catalytic decomposition of NH3 on heated tungsten in catalytic chemical vapor deposition (Cat-CVD) system. The surface of SiO2/Si(100) was nitrided at temperatures as low as 200°C. X-ray photoelectron spectroscopy measurements revealed that incorporated N atoms are bound to Si atoms and O atoms and located top-surface of SiO2.


Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3363
Author(s):  
Chi Zhang ◽  
Majiaqi Wu ◽  
Pengchang Wang ◽  
Maoliang Jian ◽  
Jianhua Zhang ◽  
...  

In this paper, the environmental stability of silicon nitride (SiNx) films deposited at 80 °C by plasma-enhanced chemical vapor deposition was studied systematically. X-ray photoelectron spectroscopy and Fourier transform infrared reflection were used to analyze the element content and atomic bond structure of the amorphous SiNx films. Variation of mechanical and optical properties were also evaluated. It is found that SiNx deposited at low temperature is easily oxidized, especially at elevated temperature and moisture. The hardness and elastic modulus did not change significantly with the increase of oxidation. The changes of the surface morphology, transmittance, and fracture extensibility are negligible. Finally, it is determined that SiNx films deposited at low-temperature with proper processing parameters are suitable for thin-film encapsulation of flexible devices.


2019 ◽  
Vol 70 (4) ◽  
pp. 329-331
Author(s):  
Petr Machac

Abstract Graphene preparation by the method of chemical vapour deposition on SiC substrates is described. Despite very low growth temperature (1080 °C) and with use of methane atmosphere, carbon layers in the form of multi-layer graphene were prepared. Graphene quality was verified by means of available analytical methods: Raman spectroscopy, X-ray photoelectron spectroscopy, Van der Paw method.


2007 ◽  
Vol 556-557 ◽  
pp. 179-182 ◽  
Author(s):  
Guo Sheng Sun ◽  
Jin Ning ◽  
Xing Fang Liu ◽  
Yong Mei Zhao ◽  
Jia Ye Li ◽  
...  

3C-SiC is a promising material for the development of microelectromechanical systems (MEMS) applications in harsh environments. This paper presents the LPCVD growth of heavily nitrogen doped polycrystalline 3C-SiC films on Si wafers with 2.0 μm-thick silicon dioxide (SiO2) films for resonator applications. The growth has been performed via chemical vapor deposition using SiH4 and C2H4 precursor gases with carrier gas of H2 in a newly developed vertical CVD chamber. NH3 was used as n-type dopant. 3C-SiC films were characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), secondary ion mass spectroscopy (SIMS), and room temperature Hall Effect measurements. It was shown that there is no voids at the interface between 3C-SiC and SiO2. Undoped 3C-SiC films show n-type conduction with resisitivity, Hall mobility, and carrier concentration at room temperature of about 0.56 ⋅cm, 54 cm2/Vs, and 2.0×1017 cm-3, respectively. The heavily nitrogen doped polycrystalline 3C-SiC with the resisitivity of less than 10-3 ⋅cm was obtained by in-situ doping. Polycrystalline SiC resonators have been fabricated preliminarily on these heavily doped SiC films with thickness of about 2 μm. Resonant frequency of 49.1 KHz was obtained under atmospheric pressure.


2005 ◽  
Vol 879 ◽  
Author(s):  
Scott K. Stanley ◽  
John G. Ekerdt

AbstractGe is deposited on HfO2 surfaces by chemical vapor deposition (CVD) with GeH4. 0.7-1.0 ML GeHx (x = 0-3) is deposited by thermally cracking GeH4 on a hot tungsten filament. Ge oxidation and bonding are studied at 300-1000 K with X-ray photoelectron spectroscopy (XPS). Ge, GeH, GeO, and GeO2 desorption are measured with temperature programmed desorption (TPD) at 400-1000 K. Ge initially reacts with the dielectric forming an oxide layer followed by Ge deposition and formation of nanocrystals in CVD at 870 K. 0.7-1.0 ML GeHx deposited by cracking rapidly forms a contacting oxide layer on HfO2 that is stable from 300-800 K. Ge is fully removed from the HfO2 surface after annealing to 1000 K. These results help explain the stability of Ge nanocrystals in contact with HfO2.


1999 ◽  
Vol 567 ◽  
Author(s):  
Renee Nieh ◽  
Wen-Jie Qi ◽  
Yongjoo Jeon ◽  
Byoung Hun Lee ◽  
Aaron Lucas ◽  
...  

ABSTRACTBa0.5Sr0.5TiO3 (BST) is one of the high-k candidates for replacing SiO2 as the gate dielectric in future generation devices. The biggest obstacle to scaling the equivalent oxide thickness (EOT) of BST is an interfacial layer, SixOy, which forms between BST and Si. Nitrogen (N2) implantation into the Si substrate has been proposed to reduce the growth of this interfacial layer. In this study, capacitors (Pt/BST/Si) were fabricated by depositing thin BST films (50Å) onto N2 implanted Si in order to evaluate the effects of implant dose and annealing conditions on EOT. It was found that N2 implantation reduced the EOT of RF magnetron sputtered and Metal Oxide Chemical Vapor Deposition (MOCVD) BST films by ∼20% and ∼33%, respectively. For sputtered BST, an implant dose of 1×1014cm−;2 provided sufficient nitrogen concentration without residual implant damage after annealing. X-ray photoelectron spectroscopy data confirmed that the reduction in EOT is due to a reduction in the interfacial layer growth. X-ray diffraction spectra revealed typical polycrystalline structure with (111) and (200) preferential orientations for both films. Leakage for these 50Å BST films is on the order of 10−8 to 10−5 A/cm2—lower than oxynitrides with comparable EOTs.


Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 937
Author(s):  
Yingying Hu ◽  
Md Rasadujjaman ◽  
Yanrong Wang ◽  
Jing Zhang ◽  
Jiang Yan ◽  
...  

By reactive DC magnetron sputtering from a pure Ta target onto silicon substrates, Ta(N) films were prepared with different N2 flow rates of 0, 12, 17, 25, 38, and 58 sccm. The effects of N2 flow rate on the electrical properties, crystal structure, elemental composition, and optical properties of Ta(N) were studied. These properties were characterized by the four-probe method, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry (SE). Results show that the deposition rate decreases with an increase of N2 flows. Furthermore, as resistivity increases, the crystal size decreases, the crystal structure transitions from β-Ta to TaN(111), and finally becomes the N-rich phase Ta3N5(130, 040). Studying the optical properties, it is found that there are differences in the refractive index (n) and extinction coefficient (k) of Ta(N) with different thicknesses and different N2 flow rates, depending on the crystal size and crystal phase structure.


Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 510
Author(s):  
Yongqiang Pan ◽  
Huan Liu ◽  
Zhuoman Wang ◽  
Jinmei Jia ◽  
Jijie Zhao

SiO2 thin films are deposited by radio frequency (RF) plasma-enhanced chemical vapor deposition (PECVD) technique using SiH4 and N2O as precursor gases. The stoichiometry of SiO2 thin films is determined by the X-ray photoelectron spectroscopy (XPS), and the optical constant n and k are obtained by using variable angle spectroscopic ellipsometer (VASE) in the spectral range 380–1600 nm. The refractive index and extinction coefficient of the deposited SiO2 thin films at 500 nm are 1.464 and 0.0069, respectively. The deposition rate of SiO2 thin films is controlled by changing the reaction pressure. The effects of deposition rate, film thickness, and microstructure size on the conformality of SiO2 thin films are studied. The conformality of SiO2 thin films increases from 0.68 to 0.91, with the increase of deposition rate of the SiO2 thin film from 20.84 to 41.92 nm/min. The conformality of SiO2 thin films decreases with the increase of film thickness, and the higher the step height, the smaller the conformality of SiO2 thin films.


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