Structural Defects of Silicon Epitaxy and Epi/Substrate Interface Related to Improper In-Situ Surface Cleaning at Low Temperatures

1990 ◽  
Vol 202 ◽  
Author(s):  
Tri-Rung Yew ◽  
Rafael Reif
Keyword(s):  
Defect Formation ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Surface Cleaning ◽  
Structural Defects ◽  
Plasma Cleaning ◽  
Substrate Interface ◽  
Silicon Epitaxy ◽  
Pressure Chemical

ABSTRACTThis paper investigates the defect formation at the epi/substrate interface and epitaxial layers due to an improper in–situ Ar or Ar/H2 plasma cleaning at 500–800 °C Deposition process was carried out immediately after the in–situ cleaning process by ultralow pressure chemical vapor deposition process (ULPCVD) from SiH4/H2. Characteristics of the defects and their relationship with damage or impurity contaminations at the interface are presented. Finally, an optimum cleaning condition which ensures high quality epitaxial growth is addressed.

In Situ Phosphorus-Doped Poly-Si by Low Pressure Chemical Vapor Deposition for Passivating Contacts

2020 ◽  
Author(s):  
Meric Firat ◽  
Hariharsudan Sivaramakrishnan Radhakrishnan ◽  
Maria Recaman Payo ◽  
Filip Duerinckx ◽  
Rajiv Sharma ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Low Pressure ◽  
Pressure Chemical ◽  
Phosphorus Doped

scholarly journals Carbon-Involved Near-Surface Evolution of Cobalt Catalyst during Reaction: An in-situ Study

2020 ◽  
Author(s):  
Feng Yang ◽  
Haofei Zhao ◽  
Wu Wang ◽  
Qidong Liu ◽  
Xu Liu ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Carbon Diffusion ◽  
Deposition Process ◽  
Catalytic Performance ◽  
Surface Evolution ◽  
Near Surface ◽  
Co Catalysts ◽  
Transmission Electron ◽  
Walled Carbon Nanotubes

Abstract When carbon-containing species are involved in reactions catalyzed by transition metals at high temperature, the diffusion of carbon on/in catalysts dramatically influence the catalytic performance. Acquiring information on the carbon-diffusion-involved evolution of catalysts at atomic level is crucial for understanding the reaction mechanism yet also challenging. For the chemical vapor deposition process of single-walled carbon nanotubes (SWCNTs), we developed methodologies to record in-situ the near-surface structural and chemical evolution of Co catalysts with carbon permeation using an aberration-corrected environmental transmission electron microscope and the synchrotron X-ray absorption spectroscopy. The nucleation and growth of SWCNTs were linked with the partial carbonization of catalysts and the alternating dissolvement-precipitation of carbon in catalysts. The dynamics of carbon atoms in catalysts brings deeper insight into the growth mechanism of SWCNTs and also sheds light on inferring mechanisms of more reactions. The methodologies developed here will find broad applications in studying catalytic and other processes.

Fabrication and electrochemical characterization of super-capacitor based on three-dimensional composite structure of graphene and a vertical array of carbon nanotubes

2018 ◽  
Vol 52 (22) ◽  
pp. 3039-3044 ◽  
Author(s):  
Daniel Choi ◽  
Eui-Hyeok Yang ◽  
Waqas Gill ◽  
Aaron Berndt ◽  
Jung-Rae Park ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Vapor Deposition ◽  
Composite Structure ◽  
Graphene Layer ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Silicon Substrates ◽  
Vertical Array ◽  
Pressure Chemical

We have demonstrated a three-dimensional composite structure of graphene and carbon nanotubes as electrodes for super-capacitors. The goal of this study is to fabricate and test the vertically grown carbon nanotubes on the graphene layer acting as a spacer to avoid self-aggregation of the graphene layers while realizing high active surface area for high energy density, specific capacitance, and power density. A vertical array of carbon nanotubes on silicon substrates was grown by a low-pressure chemical vapor deposition process using anodized aluminum oxide nanoporous template fabricated on silicon substrates. Subsequently, a graphene layer was grown by another low-pressure chemical vapor deposition process on top of a vertical array of carbon nanotubes. The Raman spectra confirmed the successful growth of carbon nanotubes followed by the growth of high-quality graphene. The average measured capacitance of the three-dimensional composite structure of graphene-carbon nanotube was 780 µFcm−2 at 100 mVs−1.

Impact of In Situ NH3 pre-treatment of LPCVD SiN passivation on GaN HEMT performance

2022 ◽  
Author(s):  
Ding-Yuan Chen ◽  
Axel R Persson ◽  
Kai Hsin Wen ◽  
Daniel Sommer ◽  
Jan Gruenenpuett ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Low Pressure ◽  
Untreated Sample ◽  
Pressure Chemical ◽  
Gan Hemts ◽  
Pre Treatment ◽  
The Impact

Abstract The impact on the performance of GaN HEMTs of in situ ammonia (NH3) pre-treatment prior to the deposition of silicon nitride (SiN) passivation with low-pressure chemical vapor deposition is investigated. Three different NH3 pre-treatment durations (0, 3, and 10 minutes) were compared in terms of interface properties and device performance. A reduction of oxygen at the interface between SiN and epi-structure is detected by Scanning Transmission Electron Microscopy-Electron Energy Loss Spectroscopy measurements in the sample subjected to 10 minutes of pre-treatment. The samples subjected to NH3 pre-treatment show a reduced surface-related current dispersion of 9 % (compared to 16% for the untreated sample), which is attributed to the reduction of oxygen at the SiN/epi interface. Furthermore, NH3 pre-treatment for 10 minutes significantly improves the current dispersion uniformity from 14.5 % to 1.9 %. The reduced trapping effects result in a high output power of 3.4 W/mm at 3 GHz (compared to 2.6 W/mm for the untreated sample). These results demonstrate that the in situ NH3 pre-treatment before low-pressure chemical vapor deposition of SiN passivation is critical and can effectively improves the large-signal microwave performance of GaN HEMTs.

scholarly journals X-ray Based in Situ Investigation of Silicon Growth Mechanism Dynamics—Application to Grain and Defect Formation

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 555 ◽  
Author(s):  
Hadjer Ouaddah ◽  
Maike Becker ◽  
Thècle Riberi-Béridot ◽  
Maria Tsoutsouva ◽  
Vasiliki Stamelou ◽  
...  
Keyword(s):  
High Temperature ◽  
Defect Formation ◽  
Imaging Techniques ◽  
Original System ◽  
Bragg Diffraction ◽  
Grain Structure ◽  
Structural Defects ◽  
X Ray ◽  
In Situ Investigation

To control the final grain structure and the density of structural crystalline defects in silicon (Si) ingots is still a main issue for Si used in photovoltaic solar cells. It concerns both innovative and conventional fabrication processes. Due to the dynamic essence of the phenomena and to the coupling of mechanisms at different scales, the post-mortem study of the solidified ingots gives limited results. In the past years, we developed an original system named GaTSBI for Growth at high Temperature observed by Synchrotron Beam Imaging, to investigate in situ the mechanisms involved during solidification. X-ray radiography and X-ray Bragg diffraction imaging (topography) are combined and implemented together with the running of a high temperature (up to 2073 K) solidification furnace. The experiments are conducted at the European Synchrotron Radiation Facility (ESRF). Both imaging techniques provide in situ and real time information during growth on the morphology and kinetics of the solid/liquid (S/L) interface, as well as on the deformation of the crystal structure and on the dynamics of structural defects including dislocations. Essential features of twinning, grain nucleation, competition, strain building, and dislocations during Si solidification are characterized and allow a deeper understanding of the fundamental mechanisms of its growth.

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