Ion Milling Damage in InP and GaAs

ABSTRACTNear-surface damage created by Ar+ ion milling in InP and GaAs was characterized by capacitance-voltage, current-voltage, photoluminescence, ion channeling and transmission electron microscopy. We find no evidence of amorphous layer formation in either material even for Ar+ ion energies of 800eV. Low ion energies (200eV) create thin (≤100 Å) damaged regions which can be removed by annealing at 500°C. Higher ion energies (≤500 eV) create more thermally stable damaged layers which actually show higher backscattering yields after 500°C annealing. Heating to 800°C is required to restore the near-surface crystallinity, although a layer of extended defects forms in GaAs after such a treatment. No dislocations are observed in InP after this type of annealing. The electrical characteristics of both InP and GaAs after ion milling at ≥500 eV cannot be restored by annealing, and it is necessary to remove the damaged surface by wet chemical etching. For the same Ar+ ion energies the damaged layers are deeper for InP than for GaAs-after 500 eV ion milling at 45° incidence angle, removal of ∼485 Å and ∼650 Å from GaAs and InP respectively restores the initial current-voltage charaeteristics of simple Schottky diodes.

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Influence of Ar Implantation on the Precipitation in Au Ion Irradiated AISI 316L Solution Annealed Alloy

MRS Advances ◽

10.1557/adv.2018.414 ◽

2018 ◽

Vol 3 (31) ◽

pp. 1799-1805 ◽

Cited By ~ 5

Author(s):

Ítalo M. Oyarzabal ◽

Mariana de M. Timm ◽

Willian M. Pasini ◽

Franciele S. M. de Oliveira ◽

Francine Tatsch ◽

...

Keyword(s):

Extended Defects ◽

Aisi 316L ◽

Ion Milling ◽

High Concentration ◽

Plan View ◽

Near Surface ◽

Transmission Electron ◽

Precipitate Growth ◽

Damage Content ◽

Steel Foils

ABSTRACT200 μm thick solution annealed AISI 316L stainless steel foils were implanted with Ar ions to produce a 0.25 at. % concentration-depth plateau extending from the near surface to a depth of ≈ 250 nm, and then annealed at 550°C for 2 hours to form small Ar bubbles and Ar-vacancy clusters. Distinct sets of samples (including control ones without Ar) were irradiated at the temperature of 550 °C with Au ions accelerated at 5 MeV to produce an average damage content about ≈36 dpa at the region containing the Ar plateau. These samples were investigated by transmission electron microscopy using plan-view specimens prepared by ion milling. In contrast with the control samples where the irradiation causes the formation of a high concentration of extended defects and large cavities, carbonite precipitation of 1:1 metal-carbon (MC) content with a cubic structure occurs only in the samples containing the Ar bubbles. This precipitation phenomenon is not commonly observed in the literature. The results are interpreted considering that the precipitate growth process requires the emission of vacancies which are synergistically absorbed by the growth of the Ar bubbles.

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Effect of N2 Plasma Treatments on Dry Etch Damage in n- and p-type GaN

MRS Proceedings ◽

10.1557/proc-639-g3.16 ◽

2000 ◽

Vol 639 ◽

Author(s):

D.G. Kent ◽

K.P. Lee ◽

A.P. Zhang ◽

B. Luo ◽

M.E. Overberg ◽

...

Keyword(s):

Plasma Treatment ◽

Schottky Diodes ◽

Surface Region ◽

Chemical Effect ◽

Near Surface ◽

Current Voltage ◽

Extent Of Damage ◽

P Type ◽

Dry Etch ◽

N2 Plasma

ABSTRACTThe extent of damage recovery by N2 plasma treatment of previously damaged n- and p-GaN has been examined using current-voltage (I-V) characteristics from Schottky diodes. There are two contributions to the observed improvement in the I-V characteristics, namely a simple annealing effect and also a chemical effect from reactive nitrogen. However the N2 plasma treatment does not fully restore the initial electrical properties of the near-surface region.

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Formation and Properties of Schottky Diodes on 4H-SiC after High Temperature Annealing with Graphite Encapsulation

Materials Science Forum ◽

10.4028/www.scientific.net/msf.527-529.915 ◽

2006 ◽

Vol 527-529 ◽

pp. 915-918 ◽

Cited By ~ 1

Author(s):

Y. Wang ◽

M.K. Mikhov ◽

B.J. Skromme

Keyword(s):

High Temperature ◽

Ideality Factor ◽

Schottky Diodes ◽

Extended Defects ◽

High Temperature Annealing ◽

Force Microscopy ◽

Atomic Force ◽

Current Voltage ◽

Encapsulation Method ◽

The Impact

The impact of high temperature annealing using graphite encapsulation (formed by baking photoresist) on the electrical properties of Ni Schottky diodes formed on the annealed surfaces is studied. The surface morphology is also characterized by atomic force microscopy (AFM). Annealing for 10 minutes at temperatures up to 1800 °C with graphite encapsulation actually reduces the high-current ideality factor of the diodes while raising the current-voltage barrier height (linearly extrapolated to unity ideality factor) from 1.453 V to 1.67-1.73 V. Excess leakage current occurs only in a subset of diodes, which are believed to be affected by extended defects. The AFM images show no significant surface roughening, and the graphite can be removed after processing. This encapsulation method is found to be highly effective in preserving the electronic properties of the surface during high temperature annealing.

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Ion Implantation Damage and Annealing in GaSb

MRS Proceedings ◽

10.1557/proc-316-185 ◽

1993 ◽

Vol 316 ◽

Author(s):

S. Iyer ◽

R. Parakkat ◽

B. Patnaik ◽

N. Parikh ◽

S. Hegde

Keyword(s):

Ion Implantation ◽

Surface Damage ◽

Liquid Nitrogen Temperature ◽

Amorphous Layer ◽

Implantation Technique ◽

Near Surface ◽

Projected Range ◽

Implantation Damage ◽

Pb Ions ◽

Better Than

ABSTRACTIon implantation technique is being investigated as an alternate technique for doping GaSb. Hence an understanding of the production and removal of the damage is essential. In this paper, we report on the damages produced by implantation of Te, Er, Hg and Pb ions into undoped (100) GaSb single crystals and their recovery by Rutherford backscattering (RBS)/channeling. The implantations of 1013 to 1013 ions/cm2 in GaSb were done at liquid nitrogen temperature at energies corresponding to the same projected range of 447Å. A comparison of the damage produced by the different ions and their recovery was made by RBS/channeling along <100> axis of GaSb. Near surface damage equivalent to that of an amorphous layer was observed even at lower doses. Upon annealing at 600°C for 30 sec., the Te implanted samples showed best recovery compared to others (Xmin = 11%), the value of Xmin being better than those normally observed in unimplanted Te-doped substrates.

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The Effects of Low Energy Ion-Beam Milling on the Physical and Electrical Properties of N-GaAs.

MRS Proceedings ◽

10.1557/proc-396-807 ◽

1995 ◽

Vol 396 ◽

Author(s):

W.F. Seng ◽

P.A. Barnes ◽

M.L. Lovejoy ◽

L.P. Fu ◽

G.D. Gilliland ◽

...

Keyword(s):

Ion Beam ◽

Surface Region ◽

Low Energy ◽

Ion Milling ◽

Ion Beam Etching ◽

Near Surface ◽

Contact Metallization ◽

Current Voltage ◽

Capacitance Voltage ◽

Modification Of The Surface

AbstractLow energy neutral Ar ion-beam etching of n-GaAs was investigated as a possible “cleaning” procedure prior to contact metallization. The ion-beam source energy was varied between 35 eV and 1200 eV at a fixed current density of 1 mA/cm2. The effects of ion-milling on lightly doped n-GaAs were analyzed electrically by measuring current-voltage (IV) and capacitance-voltage (CV) characteristics of Schottky barriers formed after the ion-milling. The metal semiconductor barriers were prepared immediately following ion-milling without breaking vacuum. Photoluminescence and Rutherford Backscattering (RBS) were used to determine if any physical modification of the surface and near surface region of the ion-milled substrates had occurred.

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Mechanisms in the Formation of High Quality Schottky Contacts to n-type ZnO

MRS Proceedings ◽

10.1557/proc-1035-l10-06 ◽

2007 ◽

Vol 1035 ◽

Cited By ~ 1

Author(s):

Martin Ward Allen ◽

Holger von Wenckstern ◽

Marius Grundmann ◽

Stuart Hatfield ◽

Paul Jefferson ◽

...

Keyword(s):

Oxygen Vacancies ◽

Schottky Diodes ◽

Schottky Contacts ◽

Atmospheric Conditions ◽

High Quality ◽

Near Surface ◽

Polar Surface ◽

Accumulation Layer ◽

Free Energy Of Formation ◽

Current Voltage

AbstractPt, Ir, Ni, Pd, and silver oxide Schottky contacts were fabricated on the Zn-polar surface of hydrothermally grown bulk ZnO. A relationship was observed between the barrier height of the contact and the free energy of formation of the “metal” oxide. This is consistent with the dominating influence of oxygen vacancies (VO) which tend to pin the ZnO Fermi level close to the VO (+2,0) defect level at approximately EC - 0.7 eV, where EC is the conduction band minimum. Valence band x-ray photoemission spectroscopy and the current - voltage characteristics of planar Schottky diodes, measured on similar Zn-polar surfaces, showed the existence of a vacuum activated surface accumulation layer. This is possibly a consequence of the observed OH termination of the Zn-polar surface. The surface accumulation layer is compensated in atmospheric conditions by the presence of acceptor-like adsorbates, such as O2 and H2O. The formation of high quality Schottky contacts to ZnO should therefore involve the reduction of near surface oxygen vacancies and the removal of H or OH from the surface.

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Device Parametric Shift Mechanism Caused by Boron Halo Redistribution Resulting from Dose Rate Dependence of SDE Implant

MRS Proceedings ◽

10.1557/proc-864-e4.32 ◽

2005 ◽

Vol 864 ◽

Author(s):

Ukyo Jeong ◽

Jinning Liu ◽

Baonian Guo ◽

Kyuha Shim ◽

Sandeep Mehta

Keyword(s):

Surface Region ◽

Amorphous Region ◽

Amorphous Layer ◽

High Dose ◽

Extended Defects ◽

Dislocation Loops ◽

Near Surface ◽

Enhanced Diffusion ◽

Dose Rates ◽

Pile Up

AbstractChange in dopant diffusion was observed for Arsenic source drain extension (SDE) implants when they were performed at various dose rates. The high dose SDE implant amorphizes the surface of the silicon substrate and the thickness of the amorphous layer is strongly influenced by the rate of dopant bombardment. It is well known that the ion implantation process introduces excess interstitials. While the amorphous region is completely re-grown into single crystal during subsequent anneal without leaving behind extended defects, interstitials that are injected beyond the amorphous layer lead to formation of {311} defects or dislocation loops in the end of range region. During thermal processing, these extended defects dissolve, release interstitials, which in turn lead to transient enhanced diffusion of underlying Boron halo dopant. Dopant depth profiles measured by SIMS revealed different amount of Boron pile-up in the near surface region, corresponding to different SDE implant dose rates. In CMOS devices, this surface pile-up would correlate with a Boron pile-up in the channel region that would lead to a shift in transistor characteristics. Through this investigation, we were able to explain the mechanism causing device characteristics shift resulted from SDE implant with the same dose and energy but different dose rates.

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Comparison of Ion-Milling Techniques For Cross-Sectional TEM of Semiconductors

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100117807 ◽

1985 ◽

Vol 43 ◽

pp. 166-167

Author(s):

Julia T. Luck ◽

C. W. Boggs ◽

S. J. Pennycook

Keyword(s):

Analytical Techniques ◽

Sample Surface ◽

Ion Milling ◽

Cross Sectional ◽

Reliable Technique ◽

Near Surface ◽

Transmission Electron ◽

Thin Region ◽

Transient Thermal

The use of cross-sectional Transmission Electron Microscopy (TEM) has become invaluable for the characterization of the near-surface regions of semiconductors following ion-implantation and/or transient thermal processing. A fast and reliable technique is required which produces a large thin region while preserving the original sample surface. New analytical techniques, particularly the direct imaging of dopant distributions, also require good thickness uniformity. Two methods of ion milling are commonly used, and are compared below. The older method involves milling with a single gun from each side in turn, whereas a newer method uses two guns to mill from both sides simultaneously.

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Preparation of Backthinned Ceramic Specimens

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100117881 ◽

1985 ◽

Vol 43 ◽

pp. 182-183

Author(s):

A. T. Fisher ◽

P. Angelini

Keyword(s):

Electron Microscopy ◽

Analytical Electron Microscopy ◽

Vacuum System ◽

Back Surface ◽

Surface Microstructure ◽

Ion Milling ◽

Near Surface ◽

Depth Profiles ◽

Analytical Electron ◽

Ion Implanted

Analytical electron microscopy (AEM) of the near surface microstructure of ion implanted ceramics can provide much information about these materials. Backthinning of specimens results in relatively large thin areas for analysis of precipitates, voids, dislocations, depth profiles of implanted species and other features. One of the most critical stages in the backthinning process is the ion milling procedure. Material sputtered during ion milling can redeposit on the back surface thereby contaminating the specimen with impurities such as Fe, Cr, Ni, Mo, Si, etc. These impurities may originate from the specimen, specimen platform and clamping plates, vacuum system, and other components. The contamination may take the form of discrete particles or continuous films [Fig. 1] and compromises many of the compositional and microstructural analyses. A method is being developed to protect the implanted surface by coating it with NaCl prior to backthinning. Impurities which deposit on the continuous NaCl film during ion milling are removed by immersing the specimen in water and floating the contaminants from the specimen as the salt dissolves.

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