Ion Beam Etch for Patterning of Resistive RAM (ReRAM) Devices

ABSTRACTWe investigate the feasibility of inert ion beam etch (IBE) for subtractive patterning of ReRAM-type structures. We report on the role of the angle-dependent ion beam etch rates in device area control and the minimization of sidewall re-deposition. The etch rates of key ReRAM materials are presented versus incidence angle and ion beam energy. As the ion beam voltage is increased, we demonstrate a significant enhancement in the relative etch rate at glancing incidence (for example, by a factor of 2 for HfO2). Since the feature sidewall is typically exposed to glancing incidence, this energy-dependence plays a role in optimization of the feature shape and in sidewall re-deposition removal.We present results of SRIM simulations to estimate depth of ion-bombardment damage to the TMO sidewall. Damage is minimized by minimizing ion energy; its depth can be reduced by roughly a factor of 5 over typical IBE energy ranges. For example, ion energies of less than ∼250 eV are indicated to maintain damage below ∼1nm. Multi-angle and multi-energy etch schemes are proposed to maximize sidewall angle and minimize damage, while eliminating re-deposition across the TMO. We utilize 2-D geometry/3-D etch model to simulate IBE patterning of tight-pitched ReRAM features, and generate etched feature shapes.

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Room Temperature Nitridation and Oxidation of Si, Ge and Mbegrown Sige Using Low Energy Ion Beams (0.1-1 Kev).

MRS Proceedings ◽

10.1557/proc-223-235 ◽

1991 ◽

Vol 223 ◽

Author(s):

O. Vancauwenberghe ◽

O. C. Hellman ◽

N. Herbots ◽

J. L. Olson ◽

W. J. Tan ◽

...

Keyword(s):

Room Temperature ◽

Ion Beam ◽

Film Properties ◽

Dielectric Thin Films ◽

Ion Energy ◽

Insulating Films ◽

Ion Energies ◽

Energy Dependent

ABSTRACTDirect Ion Beam Nitridation (IBN) and Oxidation (IBO) of Si, Ge, and Si0.8Ge0.2 were investigated at room temperature as a function of ion energy. The ion energies were selected between 100 eV and 1 keV to establish the role of energy on phase formation and film properties. Si0.8Ge0.2 films were grown by MBE on Si (100) and transferred in UHV to the ion beam processing chamber. The modification of composition and chemical binding was measured as a function of ion beam exposure by in situ XPS analysis. The samples were nitridized or oxidized using until the N or O 1s signal reached saturation for ion doses between 5×1016 to 1×1017 ions/cm2. Combined characterization by XPS, SEM, ellipsometry and cross-section TEM showed that insulating films of stoichiometric SiO2 and Si-rich Si3N4 were formed during IBO and IBN of Si at all energies used. The formation of Ge dielectric thin films by IBO and IBN was found to be strongly energy dependent and insulating layers could be grown only at the lower energies (E ≤ 200 eV). In contrast to pure Ge, insulating SiGe-oxide and SiGe-nitride were successfully formed on Si0.8Ge0.20.2 at all energies studied.

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Kinetics of ion beam nitridation (IBN) of Si and of MBE-grown Ge and SixGe1−x alloys: The role of ion energy, ion dose and substrate temperature

Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms ◽

10.1016/0168-583x(92)95821-8 ◽

1992 ◽

Vol 67 (1-4) ◽

pp. 301-307 ◽

Cited By ~ 18

Author(s):

O.C. Hellman ◽

N. Herbots ◽

O. Vancauwenberghe

Keyword(s):

Substrate Temperature ◽

Ion Beam ◽

Ion Energy ◽

Kinetics Of

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Role of ion beam energy for crystalline growth of thin films

Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms ◽

10.1016/0168-583x(93)90814-m ◽

1993 ◽

Vol 80-81 ◽

pp. 1427-1430 ◽

Cited By ~ 11

Author(s):

Kiyoshi Ogata ◽

Yasunori Andoh ◽

Fuminori Fujimoto

Keyword(s):

Thin Films ◽

Beam Energy ◽

Ion Beam ◽

Crystalline Growth

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Dry Etching of Indium Phosphide

MRS Proceedings ◽

10.1557/proc-262-1073 ◽

1992 ◽

Vol 262 ◽

Author(s):

P. Bond ◽

P. Sengupta ◽

Kevin G. Orrman-Rossiter ◽

G. K. Reeves ◽

P. J. K. Paterson

Keyword(s):

Indium Phosphide ◽

Etch Rate ◽

Ion Beam ◽

Semiconductor Industry ◽

Building Blocks ◽

Photonic Devices ◽

Ion Energy ◽

Growth Area ◽

Argon Ion ◽

Main Growth

ABSTRACTIndium Phosphide (InP) based multilayer structures are becoming increasingly important in the semiconductor industry with optoelectronic applications being the main growth area. Mesa type structures with finely controlled width and etch angle, often form the building blocks for many of these photonic devices. Traditional wet etching techniques have often proved to be inadequate for the required anisotropie removal of material. This paper presents the results of etching semi-insulating InP (100) using a combination of an Argon ion beam and a reactive gas, CCl2F2 (Freon 12). It was found that the etch rate was enhanced by increasing the ion energy and by the addition of CCl2F2. Auger electron spectroscopy revealed that the increased etch rate was accompanied by an increase in the surface indium concentration and at low ion beam energies carbon build-up retarded the etch rate. The optimum etch angle to fabricate 3μm waveguides was found to be 22° to the surface normal, however Schottky contacts to these structures were unsuccessful.

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Plasma Chemistries for Dry Etching GaN, AIN, InGaN and InAIN

MRS Proceedings ◽

10.1557/proc-421-309 ◽

1996 ◽

Vol 421 ◽

Author(s):

S. J. Pearton ◽

C. B. Vartuli ◽

J. W. Lee ◽

S. M. Donovan ◽

J. D. MacKenzie ◽

...

Keyword(s):

Hydrogen Plasma ◽

Critical Factor ◽

Dry Etching ◽

Ion Energies ◽

Volatile Products ◽

Etch Rates

AbstractEtch rates up to 7,000Å/min. for GaN are obtained in Cl2/H2/Ar or BCl3/Ar ECR discharges at 1–3mTorr and moderate dc biases. Typical rates with HI/H2 are about a factor of three lower under the same conditions, while CH4/H2 produces maximum rates of only ˜2000Å/min. The role of additives such as SF6, N2, H2 or Ar to the basic chlorine, bromine, iodine or methane-hydrogen plasma chemistries are discussed. Their effect can be either chemical ( in forming volatile products with N) or physical ( in breaking bonds or enhancing desorption of the etch products). The nitrides differ from conventional III-V's in that bondbreaking to allow formation of the etch products is a critical factor. Threshold ion energies for the onset of etching of GaN, InGaN and InAlN are ≥75eV.

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Role of Ions in Bias Enhanced Nucleation of Diamond

MRS Proceedings ◽

10.1557/proc-388-177 ◽

1995 ◽

Vol 388 ◽

Cited By ~ 1

Author(s):

J.M. Lannon ◽

J.S. Gold ◽

Cd. Stinespring

Keyword(s):

Thin Films ◽

Silicon Carbide ◽

Surface Composition ◽

Hydrogen Ions ◽

Ion Energy ◽

Transfer Processes ◽

Ion Interactions ◽

Ion Energies

AbstractIon-surface interactions are thought to play a role in bias enhanced nucleation of diamond. To explore this hypothesis and understand the mechanisms, surface studies of hydrogen and hydrocarbon ion interactions with silicon and silicon carbide have been performed. the experiments were carried out at room temperature and used in-situ auger analyses to monitor the surface composition of thin films produced or modified by the ions. Ion energies ranged from 10 to 2000 eV. Hydrogen ions were found to modify silicon carbide thin films by removing silicon and converting the resulting carbon-rich layers to a mixture of sp2- and sp3-C. the interaction of hydrocarbon ions with silicon was shown to produce a thin film containing SiC-, sp2-, and sp3-C species. IN general, the relative amount of each species formed was dependent upon ion energy, fluence, and mass. the results of these studies, interpreted in terms of chemical and energy transfer processes, provide key insights into the mechanisms of bias enhanced nucleation.

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1X Thin Films Prepared By Mass Separated Ion Beam Deposition

MRS Proceedings ◽

10.1557/proc-354-93 ◽

1994 ◽

Vol 354 ◽

Cited By ~ 15

Author(s):

H. C. Hofsäss ◽

C. Ronntng ◽

U. Griesmeier ◽

M. Gross

Keyword(s):

Thermal Activation ◽

Room Temperature ◽

Ion Beam ◽

Ir Absorption ◽

Ion Energy ◽

Ion Beam Deposition ◽

Ion Energies ◽

Substrate Temperatures ◽

Absorption Measurements ◽

Beam Deposition

AbstractWe have studied the growth and the properties of CN films prepared by deposition of mass separated 12C+ and 14N+ ions. The film thickness and density were determined as a function of ion energy between 20 eV and 500 eV and for substrate temperatures of 20 °C and 350 °C. Sputtering effects limit the maximum N concentration to about 30 - 40 at.% even for ion energies as low as 20 eV. IR absorption measurements indicate predominantly C-N and C=N bonding and an amorphous or strongly disordered CN-network. For room temperature deposited CN films with N concentrations up to 25 at.% I-V curves of metal-CN-metal devices show Frenkel-Poole behavior due to field-enhanced thermal activation of localized electrons. Films deposited at 350 °C have N concentrations below 15 at.% and graphitic properties like low resistivity and a density close to graphite.

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Preparation of molybdenum nitride thin films by N+ ion implantation

Journal of Materials Research ◽

10.1557/jmr.1992.0374 ◽

1992 ◽

Vol 7 (2) ◽

pp. 374-378 ◽

Cited By ~ 24

Author(s):

J-G. Choi ◽

D. Choi ◽

L.T. Thompson

Keyword(s):

Thin Films ◽

Ion Beam ◽

Substrate Surface ◽

Molybdenum Nitride ◽

X Ray Diffraction ◽

Ion Energy ◽

Ion Channeling ◽

Ion Energies ◽

Nitrogen Ions ◽

Nitrogen Ion

A series of molybdenum nitride films were synthesized by implanting energetic nitrogen ions into molybdenum thin films. The resulting films were characterized using x-ray diffraction to determine the effects of nitrogen ion dose (4 × 1016−4 × 1017 N+/cm2), accelerating voltage (50–200 kV), and target temperature (∼298–773 K) on their structural properties. The order of structural transformation with increased incorporation of nitrogen ions into the Mo film can be summarized as follows: Mo → γ−Mo2N → δ−MoN. Nitrogen incorporation was increased by either increasing the dose or decreasing the ion energy. At elevated target temperatures the metastable B1–MoN phase was also produced. In most cases the Mo nitride crystallites formed with the planes of highest atomic density parallel to the substrate surface. At high ion energies preferential orientation developed so that the more open crystallographic directions aligned with the ion beam direction. We tentatively attributed this behavior to ion channeling effects.

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Modeling of the Ion-Beam Growth of Covalently-Bonded Diamondlike Materials

MRS Proceedings ◽

10.1557/proc-498-129 ◽

1997 ◽

Vol 498 ◽

Cited By ~ 2

Author(s):

H. C. Hofsäss ◽

M. Sebastian ◽

H. Feldermann ◽

R. Merk ◽

C. Ronning

Keyword(s):

Film Growth ◽

Ion Beam ◽

Cubic Boron Nitride ◽

Film Structure ◽

Ion Energy ◽

Covalently Bonded ◽

Ion Energies ◽

Ion Impact ◽

Impact Events ◽

Dissipation Processes

ABSTRACTA characteristic ion energy and substrate temperature dependence for the formation of tetra-hedral amorphous carbon (ta-C), cubic boron nitride (c-BN) and related diamondlike materials by ion deposition has been experimentally observed. We present an analytical model for diamondlike film growth that describes the transient modification of the film structure by successive individual ion impact events. Each ion impact is treated as a cylindrical thermal spike with a finite initial width, taking into account energy loss and energy dissipation processes. We show that rearrangement of atoms during a cylindrical spike is the dominant mechanism leading to the formation of the diamondlike phase. The model explains quantitatively the observed ion energy dependence of the sp3 bond fraction in ta-C, as well as the broad range of ion energies for which c-BN growth is observed.

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