The Oxide/Nitride Interface: a study for gate dielectrics and field passivation

2003 ◽  
Vol 786 ◽  
Author(s):  
B.P. Gila ◽  
B. Luo ◽  
J. Kim ◽  
R. Mehandru ◽  
J.R. LaRoche ◽  
...  
Keyword(s):  
Gate Dielectrics ◽  
Substrate Surface ◽  
Surface Preparation ◽  
Dielectric Materials ◽  
Ex Situ ◽  
Dielectric Films ◽  
Interface Quality ◽  
Gas Source ◽  
Gas Source Mbe

ABSTRACTThe study of the effects of substrate surface preparation of GaN, both in-situ and ex-situ and the subsequent deposition of dielectric materials is necessary to create a viable GaN FET technology. Surface preparation techniques have been explored using RHEED, AES, SIMS and C-V measurements to produce films of low interface trap density, 1–2E11 eV−1cm−2. A similar study of the as-fabricated HEMT surface was carried out to create a cleaning procedure prior to dielectric passivation. Dielectric films of Sc2O3 and MgO were deposited via gas-source MBE. Post-deposition materials characterization included AES, TEM, XRR and XPS, as well as gate pulse and isolation current measurements for the passivated HEMT devices. From this study, the relationship between the interface structure and chemistry and the quality of the oxide/nitride electrical interface has been determined. The resulting process has led to the near elimination of the current collapse phenomenon. In addition, the resulting oxide/nitride interface quality has allowed for the first demonstration of inversion in GaN.

Study of As and P Incorporation Behavior in GaAsP by Gas-Source Molecular-Beam Epitaxy

1991 ◽  
Vol 222 ◽  
Author(s):  
B. W. Liang ◽  
H. Q. Hou ◽  
C. W. Tu
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
High Energy ◽  
Ex Situ ◽  
Limited Growth ◽  
Group V ◽  
Group Iii ◽  
Gas Source ◽  
Simple Kinetic Model

ABSTRACTA simple kinetic model has been developed to explain the agreement between in situ and ex situ determination of phosphorus composition in GaAs1−xPx (x < 0.4) epilayers grown on GaAs (001) by gas-source molecular-beam epitaxy (GSMBE). The in situ determination is by monitoring the intensity oscillations of reflection high-energy-electron diffraction during group-V-limited growth, and the ex situ determination is by x-ray rocking curve measurement of GaAs1−xPx/GaAs strained-layer superlattices grown under group-III-limited growth condition.

Electrical Evaluation of the Epi/Substrate Interface Quality after Different In-Situ and Ex-Situ Low-Temperature Pre-Epi Cleaning Methods

1998 ◽  
Vol 65-66 ◽  
pp. 237-240 ◽  
Author(s):  
Matty Caymax ◽  
S. Decoutere ◽  
Erika Röhr ◽  
W. Vandervorst ◽  
Marc M. Heyns ◽  
...  
Keyword(s):  
Low Temperature ◽  
Ex Situ ◽  
Interface Quality ◽  
Substrate Interface ◽  
Cleaning Methods

Characterization of GaAs and Ge Films on (100) Silicon

1987 ◽  
Vol 91 ◽  
Author(s):  
J.-M. Baribeau ◽  
D.C. Houghton ◽  
P. MaignÉ ◽  
W.T. Moore ◽  
R.L.S. Devine ◽  
...  
Keyword(s):  
Surface Preparation ◽  
Group Iv ◽  
Ex Situ ◽  
Rapid Thermal Anneal ◽  
Defect Reduction ◽  
Group Iii ◽  
Superlattice Dislocation ◽  
Strained Layer Superlattice

ABSTRACTA UHV MBE apparatus in which the deposition of both group IV and group III-V components is possible without breaking vacuum has been utilized to compare the growth of GaAs epilayers on non-polar Si(100) and Ge coated Si(100) substrates. In addition, a comparison of GaAs epilayers grown on substrates cleaned by ex-situ techniques and on substrates given all UHV in-situ surface preparation was made. Defect reduction by the incorporation of strained-layer superlattice dislocation filters and by post-growth rapid thermal anneal (RTA) thermal cycles was also investigated. Optical and material properties comparable to MBE grown GaAs/GaAs were obtained for GaAs grown on Ge coated Si(100) substrates.

Ti-Island-Catalyzed Si Nanowire Growth by Gas-Source MBE: Morphology and Twinning

2002 ◽  
Vol 728 ◽  
Author(s):  
Qiang Tang ◽  
Xian Liu ◽  
Theodore I. Kamins ◽  
Glenn S. Solomon ◽  
James S. Harris
Keyword(s):  
Electron Microscopy ◽  
Silicon Nanowires ◽  
High Energy ◽  
Growth Direction ◽  
Epitaxial Silicon ◽  
First Order ◽  
Gas Source ◽  
Transmission Electron ◽  
Gas Source Mbe

AbstractSilicon nanowires catalyzed by Ti islands have been grown by molecular beam epitaxy (MBE) using Si2H6 as the gas source and characterized by in situ reflection high-energy electron diffraction (RHEED), scanning-electron microscopy (SEM) and transmission-electron microscopy (TEM). Approximately one monolayer of Ti was deposited on Si(001) wafers, which, during annealing, reacted with silicon and formed TiSi2 islands. After annealing, but before Si growth, the stoichiometric TiSi2 (C49) phase was observed with RHEED.The silicon nanowires are typically between 20 and 40 nanometers in diameter and several hundred nanometers long. The nanowires changed their growth direction several times during growth, resulting in complex RHEED patterns, which can be matched very well by simulated RHEED patterns calculated assuming that the nanowires change their direction by twinning along (111) planes. RHEED patterns of epitaxial silicon nanowires, first-order twinned nanowires (twinned relative to the substrate orientation), second-order twinned nanowires (twinned relative to the first-order twin), and TiSi2 were observed.

Deposition and characterization of HfO2 high k dielectric films

2004 ◽  
Vol 19 (6) ◽  
pp. 1775-1782 ◽  
Author(s):  
Wai Lo ◽  
Arvind Kamath ◽  
Shreyas Kher ◽  
Craig Metzner ◽  
Jianguo Wen ◽  
...  
Keyword(s):  
Gate Dielectrics ◽  
Chemical Vapor ◽  
Complementary Metal Oxide Semiconductor ◽  
Deposition Process ◽  
Dielectric Materials ◽  
Growth Conditions ◽  
Oxide Semiconductor ◽  
Dielectric Films ◽  
Equivalent Thickness ◽  
Vapor Deposition Technique

As the scaling of complementary metal-oxide-semiconductor (CMOS) transistors proceeds, the thickness of the SiO2 gate dielectrics shrinks rapidly and results in higher gate leakage currents. High k dielectric materials are acknowledged to be the possible solutions to this challenge, as their higher k values (e.g., 15–50) raise the physical thickness of the dielectrics that provide similar equivalent thickness of a thinner SiO2 film. In order for the high k materials to be applicable in CMOS devices, there should exist deposition technologies that can deposit highly uniform films over Si wafers with diameters as large as 200 mm. This report discusses the deposition process and the correlation between the growth conditions, structural and dielectric properties of HfO2, which is one of the most promising high k dielectric materials. Judging from the thickness uniformity, surface roughness, k value, and interfacial density of state of the HfO2 films, the metalorganic chemical vapor deposition technique was identified to be suitable for growing HfO2 films targeted at applications as CMOS gate dielectrics.

scholarly journals Surface Evolution of 4H-SiC(0001) during In Situ Surface Preparation and its Influence on Graphene Properties

2013 ◽  
Vol 740-742 ◽  
pp. 157-160 ◽  
Author(s):  
Jawad ul Hassan ◽  
Axel Meyer ◽  
Semih Cakmakyapan ◽  
Ozgur Kazar ◽  
Jan Ingo Flege ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Growth Process ◽  
Substrate Surface ◽  
Surface Preparation ◽  
Surface Evolution ◽  
Surface Step ◽  
Graphene Growth ◽  
Graphene Layers ◽  
Step Structure

The evolution of SiC surface morphology during graphene growth process has been studied through the comparison of substrate surface step structure after in-situ etching and graphene growth in vacuum. Influence of in-situ substrate surface preparation on the properties of graphene was studied through the comparison of graphene layers on etched and un-etched substrates grown under same conditions.

Laser-Reflectance Interferometry Measurements of Diamond-Film Growth

MRS Bulletin ◽  
1995 ◽  
Vol 20 (5) ◽  
pp. 29-31 ◽  
Author(s):  
Christopher D. Zuiker ◽  
Dieter M. Gruen ◽  
Alan R. Krauss
Keyword(s):  
Film Thickness ◽  
Film Growth ◽  
Substrate Surface ◽  
Diamond Films ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Index Of Refraction ◽  
Ex Situ ◽  
Laser Reflectance

The remarkable properties of diamond, including its hardness, chemical inertness, high thermal conductivity, low coefficient of friction, optical transparency, and semiconducting properties, have led to considerable research in the area of diamond thin-film deposition. Diamond films have been characterized ex situ by a large number of diagnostic techniques including Raman spectroscopy, x-ray diffraction, SEM, and TEM. In situ diagnostics, which can provide information in real time as the film is growing, are less common.Laser-reflectance interferometry (LRI) has been used to monitor the growth of diamond films in situ. The technique involves measuring the intensity of a laser beam reflected from the substrate surface on which the film is growing. The reflected beam is the sum of beams reflected by the gas-diamond interface and the diamond-silicon interface. Oscillations in the reflectivity are observed as the film grows because of interference between the reflected beams. Each oscillation indicates an increase in film thickness of λ/2n, where λ is the laser wavelength and n is the index of refraction of the film. If the index of refraction of the film is known, the thickness and growth rate can be determined in situ. For LRI measurements with 632.8-nm-wavelength HeNe lasers, the index of refraction of diamond films has been found to be within 10% of the bulk diamond value of 2.4. Each oscillation therefore indicates an increase in film thickness of 0.13 μm.The reflectivity measured by LRI is also affected by scattering because of surface roughness.

A study of ruthenium ultrathin film nucleation on pretreated SiO2 and Hf–silicate dielectric surfaces

2007 ◽  
Vol 22 (8) ◽  
pp. 2254-2264 ◽  
Author(s):  
Filippos Papadatos ◽  
Steven Consiglio ◽  
Spyridon Skordas ◽  
Eric T. Eisenbraun ◽  
Alain E. Kaloyeros
Keyword(s):  
Grain Size ◽  
Rutherford Backscattering Spectrometry ◽  
Substrate Surface ◽  
Compressive Strain ◽  
Chemical Vapor ◽  
Nucleation And Growth ◽  
Ex Situ ◽  
Organic Chemical ◽  
Nucleation Density

This study explored the effects of substrate surface pretreatments on the nucleation and growth of metal–organic chemical vapor deposited ruthenium. In situ plasma (dry), featuring O2, Ar, and H2/Ar chemistries, and ex situ (wet) treatments, consisting of a standard RCA bath, were examined in the nucleation and growth of up to 50-nm-thick metallic Ru films on SiO2 and Hf–silicate surfaces. The resulting surface morphology, grain size, and roughness of the metallic films were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM), while Rutherford backscattering spectrometry (RBS) was used for compositional measurements. It was determined that an in situ plasma treatment using a H2/Ar yielded metallic Ru films with the highest nucleation density, smallest grain size, and lowest resistivity. Film buckling was also observed for the Ru films deposited on H2/Ar pretreated surfaces. The behavior was attributed to the presence of compressive strain. The films deposited on RCA-cleaned and Ar plasma treated surfaces exhibited very similar physical and electrical characteristics to the films grown on untreated substrates. Alternatively, the use of O2 plasma surface treatment adversely affected Ru nucleation on the SiO2 surface. Relevant mechanisms for Ru nucleation and growth on SiO2 and Hf–silicate nontreated surfaces are discussed in the context of the various predeposition dry and wet treatments.

(Negative) Electron Affinity of AlN and AlGaN Alloys

1995 ◽  
Vol 395 ◽  
Author(s):  
R.J. Nemanich ◽  
M.C. Benjamin ◽  
S.P. Bozeman ◽  
M.D. Bremser ◽  
S.W. King ◽  
...  
Keyword(s):  
Electron Affinity ◽  
Negative Electron Affinity ◽  
Atomic Orbitals ◽  
Gas Source ◽  
Gas Source Mbe ◽  
Relationship Of ◽  
The Relationship ◽  
Alloy Concentration ◽  
Theoretical Results

ABSTRACTThe electron affinity of a semiconductor defines the relationship of the vacuum level and the semiconductor band structure. It is dependent on the atomic orbitals of the material and the surface termination. We report experimental and theoretical results that support the presence of a negative electron affinity on AlN and the Al rich AlGaN alloys. The GaN surface is found to exhibit a (positive) electron affinity of 3.3eV. The experimental measurements employ UV-photoemission spectroscopy on in situ gas-source MBE samples and on CVD samples. Theoretical results indicate that the (negative) electron affinity of AlN depends sensitively on the surface reconstruction and adatom termination. The experimental dependence of the electron affinity on alloy concentration is presented. The results indicate that AlGaN alloys with band gap similar or greater than that of diamond will exhibit a negative electron affinity. Field emission results are reported, and the characteristics are similar to those obtained from a diamond film. Issues related to cold cathode electronic devices based on NEA surfaces are noted.

Si(100) Surface Preparation by In-Situ or in-Vacuo Exposure to Remotely Plasma-Generated Atomic Hydrogen: Applications to Deposited SiO2 and Epitaxial Growth of Si

1990 ◽  
Vol 202 ◽  
Author(s):  
T. Yasuda ◽  
Y. Ma ◽  
S. Habermehl ◽  
S. S. Kim ◽  
G. Lucovsky ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Atomic Hydrogen ◽  
Hydrogen Plasma ◽  
Surface Preparation ◽  
Surface Cleaning ◽  
Ozone Exposure ◽  
Ex Situ ◽  
Carbon Surface ◽  
Necessary Condition

ABSTRACTThis paper addresses the in-situ/in-vacuo preparation of Si (100) substrates by hydrogen plasma cleaning prior to low temperature deposition of SiO2, or epitaxial growth of Si or Ge. The paper emphasizes the effectiveness of this type of substrate surface preparation following ex-situ wet-cleaning procedures that include: i) conventional RCA cleans; ii) modified RCA cleans, which incorporate exposure of the Si substrate to ozone, O3; and iii) ozone exposure, with all of these terminated by the removal of sacrificial oxides by dilute HF. We conclude: i) all ex-situ surface cleaning of Si (100) substrates leaves behind sub-monolayer oxygen and carbon surface contamination; ii) that virtually all of the carbon can be removed by exposure of the Si surface to atomic hydrogen at a temperature of <300°C; and iii) that a necessary condition for: (a) the formation of Si/SiO2 interfaces with low defect densities, Dit<l−3×1010cm−2-eV−1, and (b) the growth of epitaxial films of Si; is that the processed Si surface exhibit a 2×1 reconstruction, as detected by LEED or RHEED, following the exposure to atomic hydrogen.

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