Investigation of Trenched and High Temperature Annealed 4H-SiC

2014 ◽  
Vol 778-780 ◽  
pp. 742-745 ◽  
Author(s):  
Christian T. Banzhaf ◽  
Michael Grieb ◽  
Achim Trautmann ◽  
Anton J. Bauer ◽  
Lothar Frey
Keyword(s):  
High Temperature ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Substrate Surface ◽  
Oxide Semiconductor ◽  
Atom Concentration ◽  
High Temperature Anneal ◽  
Static Capacitance ◽  
Substrate Surface Roughness ◽  
Mos Structures

This study focuses on the effects of a high temperature anneal after dry etching of trenches (post-trench anneal, PTA) on 4Hsilicon carbide (4H-SiC). We aim at the optimum 4H-SiC post-trench treatment with respect to the fabrication and the operation of a trenched gate metal oxide semiconductor field effect transistor (Trench-MOSFET). PTA significantly reduces micro-trenches, also called sub-trenches [, in the corners of the bottom of the trench. This is highly beneficial in case the etched trench sidewall is used as the channel of a Trench-MOSFET. However, PTA is also shown to cause a slight enlargement of the trench width along with a considerable increase of the substrate surface roughness. In addition, X-ray photoelectron spectroscopy (XPS) depth profiles indicate an increased carbon atom concentration at the 4H-SiC surface after the high temperature PTA. The non-stoichiometric surface composition affects the quasi-static capacitance-voltage (QSCV) behavior of MOS structures using a deposited gate oxide (GOX). We assume that a sacrificial oxidation directly after the PTA could restore a stoichiometric 4H-SiC surface.

Influence of Diverse Post-Trench Processes on the Electrical Performance of 4H-SiC MOS Structures

2014 ◽  
Vol 778-780 ◽  
pp. 595-598 ◽  
Author(s):  
Christian T. Banzhaf ◽  
Michael Grieb ◽  
Achim Trautmann ◽  
Anton J. Bauer ◽  
Lothar Frey
Keyword(s):  
Dielectric Breakdown ◽  
Field Effect Transistors ◽  
Oxide Semiconductor ◽  
Electrical Performance ◽  
Breakdown Field ◽  
Static Capacitance ◽  
Capacitance Voltage ◽  
Oxide Deposition ◽  
Mos Structures ◽  
Field Strengths

This paper focuses on the evaluation of subsequent process steps (post-trench processes, PTPs) after 4H silicon carbide (4H-SiC) trench etching with respect to the electrical performance of trenched gate metal oxide semiconductor field effect transistors (Trench-MOSFETs). Two different types of PTP were applied after 4H-SiC trench formation, a high temperature post-trench anneal (PTA) [1] and a sacrificial oxidation (SacOx) [2]. We found significantly improved electrical properties of Planar-MOS structures using a SacOx as PTP, prior to gate oxide deposition. Besides excellent quasi-static capacitance-voltage (QSCV) behavior even at T = 250 °C, charge-to-breakdown (QBD) results up to 8.8 C/cm2 at T = 200 °C are shown to be similar on trenched surfaces as well as on untrenched surfaces of SacOx-treated Planar-MOS structures. Moreover, dielectric breakdown field strengths up to 12 MV/cm have been measured on Planar-MOS structures. However, thick bottom oxide Trench-MOS structures indicate best dielectric breakdown field strengths of 9.5 MV/cm when using a trench shape rounding PTA as the PTP.

Suppression of Ni Silicide Formation by Se Passivation of Si(001)

2004 ◽  
Vol 810 ◽  
Author(s):  
Janadass Shanmugam ◽  
Michael Coviello ◽  
Darshak Udeshi ◽  
Wiley P. Kirk ◽  
Meng Tao Nano
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Semiconductor Surface ◽  
Composition Analysis ◽  
Silicide Formation ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Thermal Stability Of

ABSTRACTValence mending of a semiconductor surface, such as the Se-passivated Si(001) surface, improves the chemical and thermal stability of the surface as compared to the bare Si(001) surface. In this paper, we report the suppression of Ni silicide formation between Ni and Si(001) through monolayer passivation of Si(001) by Se. Ni was deposited on both Se-passivated and bare Si(001) surfaces. The samples were annealed at temperatures from 400°C to 700°C. Cross-sectional TEM (Transmission Electron Microscopy) revealed that Ni on bare samples reacted with Si at 400°C and formed silicide, whereas Ni on Se-passivated samples did not react with Si at 500°C. Surface composition analysis by XPS (X-Ray Photoelectron Spectroscopy) showed pure Ni surface on Se-passivated samples annealed at 400°C and 500°C, but silicide surface on bare samples annealed at the same temperatures. Hence, Se passivation suppresses the formation of Ni silicide on the Si(001) surface by over 100°C as compared to the bare Si(001) surface. These results may have important implications in source/drain engineering in sub-100 nm Si CMOS (Complementary Metal Oxide Semiconductor) devices.

Interface chemistry and electrical characteristics of 4H-SiC/SiO2 after nitridation in varying atmospheres

2018 ◽  
Vol 6 (44) ◽  
pp. 12079-12085 ◽  
Author(s):  
Anna Regoutz ◽  
Gregor Pobegen ◽  
Thomas Aichinger
Keyword(s):  
High Temperature ◽  
Metal Oxide ◽  
High Power ◽  
Photoelectron Spectroscopy ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Electrical Characteristics ◽  
Interface Chemistry ◽  
X Ray ◽  
Immense Potential

SiC has immense potential as the semiconductor for future high power metal–oxide–semiconductor devices. X-ray photoelectron spectroscopy (XPS) to systematically study the 4H-SiC/SiO2 interface after high temperature nitridation treatments in a variety of atmospheres.

scholarly journals The Role of Substrate Surface Roughness on in-Pack Aluminization Kinetics of Ni-Base Superalloy

2020 ◽  
Vol 4 (1) ◽  
pp. 15 ◽  
Author(s):  
Wojciech J. Nowak ◽  
Małgorzata Tomków ◽  
Patrycja Wierzba ◽  
Kamil Gancarczyk ◽  
Bartek Wierzba
Keyword(s):  
Surface Roughness ◽  
High Temperature ◽  
High Temperature Oxidation ◽  
Substrate Surface ◽  
Surface Preparation ◽  
Temperature Oxidation ◽  
Diffusion Layers ◽  
Substrate Surface Roughness ◽  
Effect Of Surface

The Ni-base superalloys facing high temperature require further protection against high temperature oxidation. One of the most common methods providing high temperature oxidation resistance is the production of aluminide layers (NiAl-coatings). It is known that the thickness of produced diffusion layer can be controlled by the temperature and time of aluminization process. However, no research on the effect of surface roughness on aluminization kinetics was conducted so far. Then, to elucidate the effect of surface roughness on aluminization kinetics, diffusion layers were obtained by an in-pack aluminization method on the IN 617 alloy with differently prepared surfaces, namely polished, ground using 220 grit SiC paper and 80 grit SiC paper. The obtained results revealed that different surface preparation does not affect the chemical and phase composition of produced layers. However, a strong influence of surface preparation method on aluminide layers thicknesses was observed. Namely, it was found that the increase in substrate surface roughness results in an increase of aluminization kinetics. The dependence between surface roughness and thickness of aluminide layers was found to be logarithmic. Moreover, it was found that the aluminization kinetics is influenced, especially at early stages of the aluminization process.

scholarly journals Effect of sintering temperature on adhesion of spray-on piezoelectric transducers

2016 ◽  
Vol 5 (1) ◽  
pp. 113-123 ◽  
Author(s):  
Kyle M. Sinding ◽  
Alison Orr ◽  
Luke Breon ◽  
Bernhard R. Tittmann
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Fluid Transport ◽  
Surface Composition ◽  
Substrate Surface ◽  
Sol Gel ◽  
Processing Conditions ◽  
Stainless Steel 316L ◽  
Minimum Requirement ◽  
Low Temperature Processing

Abstract. Conventionally sol-gel spray-on transducers require a high-temperature (> 700 °C) sintering process; however, this process can affect the microstructure of the substrate material. For mechanical elbows and valves utilized for fluid transport in the energy sector, the components are designed to have a specific microstructure, and deviations from these specifications can create weak points in the system. For this reason it is important to investigate how the temperature of the deposition process affects the substrate. This paper investigates the effect of high-temperature and low-temperature (< 150 °C) processing conditions on the surface composition of the substrate. Furthermore, the resultant transducers from high- and low-temperature fabrication processes are compared to determine if a low-temperature processing method is feasible. For these studies a sol-gel spray-on process is employed to deposit piezoelectric ceramics onto a stainless-steel 316L substrate. Energy-dispersive X-ray spectroscopy is utilized to determine the composition of the substrate surface before and after transducer deposition. Results indicate that the high-temperature processing conditions may alter the surface composition of the metal due to a diffusion of the metal into the ceramic, which results in a metal surface that is bonded to the ceramic. Furthermore, it is shown that low-temperature processing of spray-on transducers is a viable method for transducer fabrication where the resultant transducers meet the industry minimum requirement of 30 dB signal-to-noise ratio. In parallel simulation calculations, finite-element method (FEM) studies were performed to model the adhesive strength of the low-temperature processed transducer to the substrate surface. Comparisons between the simulations and experiments suggest that the bond strength is much greater than the commercial gel bonds and closer to hardened epoxy glue bonds. These results indicate that spray-on transducers fabricated under low-temperature processing conditions are a viable solution for leave-in-place monitoring of structures.

Preferential Sputtering of Ni3Al Single Crystals Studied Using Atom-Probe Field-Ion Microscopy and XPS

1981 ◽  
Vol 39 ◽  
pp. 16-17
Author(s):  
M.P. Thomas ◽  
A.R. Waugh ◽  
M.J. Southon ◽  
Brian Ralph
Keyword(s):  
Single Crystals ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Depth Profiling ◽  
Analytical Techniques ◽  
Atom Probe ◽  
Probe Field ◽  
Preferential Sputtering ◽  
Argon Ion Bombardment ◽  
Argon Ion

It is well known that ion-induced sputtering from numerous multicomponent targets results in marked changes in surface composition (1). Preferential removal of one component results in surface enrichment in the less easily removed species. In this investigation, a time-of-flight atom-probe field-ion microscope A.P. together with X-ray photoelectron spectroscopy XPS have been used to monitor alterations in surface composition of Ni3Al single crystals under argon ion bombardment. The A.P. has been chosen for this investigation because of its ability using field evaporation to depth profile through a sputtered surface without the need for further ion sputtering. Incident ion energy and ion dose have been selected to reflect conditions widely used in surface analytical techniques for cleaning and depth-profiling of samples, typically 3keV and 1018 - 1020 ion m-2.

CO2 Reduction to Propanol by Copper Foams: A Pre- and Post-Catalysis Study

2020 ◽  
Author(s):  
Jennifer A. Rudd ◽  
Ewa Kazimierska ◽  
Louise B. Hamdy ◽  
Odin Bain ◽  
Sunyhik Ahn ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Photoelectron Spectroscopy ◽  
Carbon Capture ◽  
Surface Composition ◽  
Co2 Reduction ◽  
Structural Rearrangement ◽  
Copper Electrode ◽  
Ex Situ ◽  
X Ray ◽  
Copper Electrodes

The utilization of carbon dioxide is a major incentive for the growing field of carbon capture. Carbon dioxide could be an abundant building block to generate higher value products. Herein, we describe the use of porous copper electrodes to catalyze the reduction of carbon dioxide into higher value products such as ethylene, ethanol and, notably, propanol. For <i>n</i>-propanol production, faradaic efficiencies reach 4.93% at -0.83 V <i>vs</i> RHE, with a geometric partial current density of -1.85 mA/cm<sup>2</sup>. We have documented the performance of the catalyst in both pristine and urea-modified foams pre- and post-electrolysis. Before electrolysis, the copper electrode consisted of a mixture of cuboctahedra and dendrites. After 35-minute electrolysis, the cuboctahedra and dendrites have undergone structural rearrangement. Changes in the interaction of urea with the catalyst surface have also been observed. These transformations were characterized <i>ex-situ</i> using scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. We found that alterations in the morphology, crystallinity, and surface composition of the catalyst led to the deactivation of the copper foams.

scholarly journals Surface Composition and Corrosion of SS 41 Carbon Steel in High Temperature Water under γ-ray Irradiation

1982 ◽  
Vol 31 (4) ◽  
pp. 254-260
Author(s):  
Akihisa Sakumoto ◽  
Masao Gotoda ◽  
Yuji Horii ◽  
Hidetaka Konno ◽  
Hiroki Tamura ◽  
...  
Keyword(s):  
High Temperature ◽  
Carbon Steel ◽  
Gamma Ray ◽  
Surface Composition ◽  
High Temperature Water ◽  
Gamma Ray Irradiation ◽  
Temperature Water
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