Boron Nitride Materials for Tribological and High Temperature High Power Devices

1997 ◽  
Vol 495 ◽  
Author(s):  
N. Badi ◽  
A. Tempez ◽  
D. Starkov ◽  
N. Medelcr ◽  
A. Bensaoula ◽  
...  
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Boron Nitride ◽  
Electron Cyclotron Resonance ◽  
Ion Beam ◽  
Damage Threshold ◽  
Laser Damage Threshold ◽  
Optical Damage ◽  
Force Microscopy ◽  
Ecr Plasma

ABSTRACTBoron nitride thin films on sapphire substrates were investigated for their tribological and optoelectronic applications. A gridless end Hall gun source and an electron cyclotron resonance (ECR) source were used for nitrogen species delivery while pure boron was evaporated at a rate of 0.2 Å/s. The surface stability of these thin films was investigated by high temperature annealing. Atomic force microscopy (AFM), friction force microscopy (FFM), and Knoop microhardness measurements were performed on the materials in order to assess their merits as tribological coatings. Finally, BN thin films were subjected to laser transient photoconductivity (TPC) experiments to determine both their optical laser damage threshold as well as their photoconductivity characteristics. For both single-pulse shot and multiple-pulse irradiation regimes, preliminary tests showed the higher the ion beam current used during growth (70–150 mA), the higher the optical damage threshold. The lower damage threshold was typical of BN films grown using an ECR plasma source and was measured to be in the range of ∼50 MW/cm2. Optical damage of films grown at ion beam currents above 100 mA was not observed at laser intensities up to few hundreds MW/cm2. A multiphoton excitation technique was utilized to obtain PC signals from this wide band gap material and preliminary results show that unusual PC voltage amplitudes as high as 0.5 V were observed.

Reactive Ion Etching of Boron Nitride and Gallium Nitride Materials in C12/Ar and BCl3/Cl2/Ar Chemistries

1998 ◽  
Vol 512 ◽  
Author(s):  
N. Medelci ◽  
A. Tempez ◽  
E. Kim ◽  
N. Badi ◽  
D. Starikov ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
High Temperature ◽  
Boron Nitride ◽  
Electron Cyclotron Resonance ◽  
Surface Composition ◽  
Ion Beam ◽  
Reactive Ion Etching ◽  
Rf Power ◽  
Ion Etching ◽  
Etch Rates

ABSTRACTBoron nitride (BN) and gallium nitride (GaN) are known as superior semiconductor materials for high power and high temperature applications. Undoped BN layers grown using ion beam and electron cyclotron resonance (ECR) assisted physical deposition on conductive GaN films have demonstrated good insulating properties. These films are thus good candidates as thin insulating layers in high temperature GaN-based device structures such as MIS diodes and MISFETs due to their close thermal expansion coefficient. In order to address the device processing issue, reactive ion etching (RIE) tests were performed on these films. Using Cl2/Ar chemistry, etch rates up to 600 Å/min were measured. These rates were found to increase linearly with increasing rf power and Cl2 flow rate. GaN layers grown by gas source MBE were also dry etched, resulting in smooth sidewalls. Etch rates up to 1,400 Å/min were achieved at 200 W rf power (-280 V d.c. bias) in a BCl3/Cl2/Ar chemistry; this is the highest RIE rate reported up to now for GaN. Using Cl2/Ar and BCl3/Cl2/Ar for BN and GaN respectively, etch selectivities in excess of 5:1 can be obtained. Finally, preliminary Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) results on residue deposition and surface composition changes as a function of the different etch conditions are presented.

Preparation of pzt thin films on Pt/Ti/SiO2 and Pt/SiO2 Substrates by ECR Plasma Enhanced DC Magnetron Multi-target Reactive Sputtering

1996 ◽  
Vol 441 ◽  
Author(s):  
Sung-Tae Kim ◽  
Hyun-Ho Kim ◽  
Moon-Yong Lee ◽  
Won-Jong Lee
Keyword(s):  
Thin Films ◽  
Lead Zirconate Titanate ◽  
Electron Cyclotron Resonance ◽  
Perovskite Phase ◽  
Early Stage ◽  
Reactive Sputtering ◽  
Deposition Process ◽  
Pzt Thin Films ◽  
Si Substrates ◽  
Ecr Plasma

AbstractPerovskite-phase lead zirconate titanate (PZT) thin films were fabricated at 4751C by the electron cyclotron resonance (ECR) plasma enhanced DC magnetron multi-target reactive sputtering method on Pt/Ti/SiO2/Si and Pt/SiO2/Si substrates. Stoichiometric perovskite PZT films were readily obtained on Pt/Ti/SiO2/Si substrates because Ti atoms which were out-diffused to the Pt surface facilitated Pb incorporation by forming lead titanate at the early stage of deposition process. Activation of oxygen by ECR plasma facilitated the oxidation reaction and Pb incorporation into the film. Thus perovskite-phase PZT can be obtained on the Pt/SiO2/Si substrate.

scholarly journals Hexagonal Boron Nitride Tunnel Barriers Grown on Graphite by High Temperature Molecular Beam Epitaxy

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Yong-Jin Cho ◽  
Alex Summerfield ◽  
Andrew Davies ◽  
Tin S. Cheng ◽  
Emily F. Smith ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
High Temperature ◽  
Molecular Beam Epitaxy ◽  
Boron Nitride ◽  
Photoelectron Spectroscopy ◽  
Molecular Beam ◽  
Hexagonal Boron Nitride ◽  
Graphite Substrate ◽  
Force Microscopy ◽  
Atomic Force

Abstract We demonstrate direct epitaxial growth of high-quality hexagonal boron nitride (hBN) layers on graphite using high-temperature plasma-assisted molecular beam epitaxy. Atomic force microscopy reveals mono- and few-layer island growth, while conducting atomic force microscopy shows that the grown hBN has a resistance which increases exponentially with the number of layers, and has electrical properties comparable to exfoliated hBN. X-ray photoelectron spectroscopy, Raman microscopy and spectroscopic ellipsometry measurements on hBN confirm the formation of sp2-bonded hBN and a band gap of 5.9 ± 0.1 eV with no chemical intermixing with graphite. We also observe hexagonal moiré patterns with a period of 15 nm, consistent with the alignment of the hBN lattice and the graphite substrate.

scholarly journals ECR Plasma Synthesis of Silicon Nitride Films ON GaAs and InSb

1993 ◽  
Vol 316 ◽  
Author(s):  
J. C. Barbour ◽  
M. L. Lovejoy ◽  
C. I. H. Ashby ◽  
A. J. Howard ◽  
J. S. Custer ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Surface Passivation ◽  
Electron Cyclotron Resonance ◽  
Ion Beam ◽  
Fold Increase ◽  
Film Stress ◽  
Dielectric Films ◽  
Plasma Synthesis ◽  
Ecr Plasma ◽  
Composition Profiles

ABSTRACTThe growth of high-quality dielectric films from Electron Cyclotron Resonance (ECR) plasmas provides for low-temperature surface passivation of compound semiconductors. Silicon nitride (SiNx) films were grown at temperatures from 30°C to 250°C on GaAs substrates. The stress in the films was measured as a function of bias applied during growth (varied from 0 to 200 V), and as a function of sample annealing treatments. Composition profiles of the samples were measured using ion beam analysis. The GaAs photoluminescence (PL) signal after SiNx growth without an applied bias (ion energy = 30 eV) was twice as large as the PL signal from the cleaned GaAs substrate. The PL signal from samples biased at -50 and -100 V indicated that damage degraded the passivation quality, while atomic force microscopy of these samples showed a three fold increase in rms surface roughness relative to unbiased samples. The sample grown with a bias of-200 V showed the largest reduction in film stress but also the smallest PL signal.

Control of Optical Performance from Er-Doped Alumina Synthesized Using An Ecr Plasma

1997 ◽  
Vol 504 ◽  
Author(s):  
J. C. Barbour ◽  
B. G. Potter
Keyword(s):  
Near Infrared ◽  
Electron Cyclotron Resonance ◽  
Ion Beam ◽  
Electron Beam Evaporation ◽  
Elastic Recoil ◽  
Elastic Recoil Detection ◽  
Ecr Plasma ◽  
Thermal Release ◽  
Simple Linear Equation ◽  
Er Doped

ABSTRACTHydrogen in deposited optical ceramics can modify the optical properties, and therefore the role of the hydrogen needs to be understood to control its effects. Erbium-doped amorphous alumina films were deposited using simultaneous electron beam evaporation of aluminum and erbium while bombarding the sample with 30 eV 02+ ions from an electron cyclotron resonance (ECR) plasma. The hydrogen content was measured, using elastic recoil detection, as a function of isochronal annealing treatments. The data was fit to a simple trap-release model in order to determine an effective activation energy for the thermal release of H from alumina and Er-doped alumina. The intensity of the ion-beam stimulated luminescence from these samples was monitored in the visible and near infrared regions as a function of the thermal treatments. In order to gain a better understanding of the influence of hydrogen, the ionoluminescence (IL) data from samples containing hydrogen were fit with a simple linear equation.

Hydrogen in Dielectric Film Formation From an Electron Cyclotron Resonance Plasma

1991 ◽  
Vol 235 ◽  
Author(s):  
J. C. Barbour ◽  
H. J. Stein
Keyword(s):  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Ion Irradiation ◽  
Film Formation ◽  
Ion Beam ◽  
Electron Cyclotron ◽  
Elastic Recoil ◽  
Elastic Recoil Detection ◽  
Ecr Plasma ◽  
The Stability

ABSTRACTThe incorporation of hydrogen into silicon nitride films grown downstream from an electron cyclotron resonance (ECR) plasma decreased rapidly with increasing substrate temperature (100–600°C). Fourier transform infra-red (FTIR) spectroscopy showed that the hydrogen in the as-grown material was primarily bonded to nitrogen. However, an applied bias of -200 V caused an increase in the number of Si-H bonds relative to N-H bonds, as a result of increased ion-beam damage. In addition, ion irradiation of an as-grown film with 175 keV Ar+ at room temperature showed that H transferred from N-H bonds to Si-H bonds without a loss of H. Elastic recoil detection (ERD) and FTIR of thermally annealed films showed that the stability of H incorporated during deposition increased with deposition temperature, and that the N-H bond was more stable than the Si-H bond above 700°C. Deuterium plasma treatments, at 600°C, of annealed films caused isotopic substitution with a conservation of bonds. Therefore, hydrogen loss from annealed films is apparently accompanied by a reduction in dangling bonds.

Optical properties and laser damage threshold of HfO2–SiO2 mixed composite thin films

2014 ◽  
Vol 53 (5) ◽  
pp. 850 ◽  
Author(s):  
Shuvendu Jena ◽  
Raj Bahadur Tokas ◽  
Nitin M. Kamble ◽  
Sudhakar Thakur ◽  
Naba Kishore Sahoo
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Damage Threshold ◽  
Laser Damage Threshold ◽  
Laser Damage ◽  
Composite Thin Films
Sign in / Sign up

Export Citation Format

Share Document