N.W. Cheung

Washington University in St. Louis

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Chenming Hu

University of California, Berkeley

Paul K. Chu

City University of Hong Kong

T. Sands

Stanford University

E.C. Jones

University of Florida

K. M. Yu

Lawrence Berkeley National Laboratory

Tao Jiang

Northwest Institute of Nuclear Technology

W.G. En

University of California, Berkeley

D. Kraus

Federal Institute For Materials Research and Testing

S. Eilerts

University of New Mexico

J. J. Lozano Bahilo

Instituto de Física Corpuscular

Cooperative Institutions

University of California, Berkeley

149

Lawrence Berkeley National Laboratory

University of California System

Brookhaven National Laboratory

California Institute of Technology

University of Pittsburgh

University of California, San Diego

Stanford University

Centre National de la Recherche Scientifique

University of Hong Kong

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Metallization of GaN Thin Films Prepared by Ion Beam Assisted Molecular Beam Epitaxy

MRS Proceedings (1994)

J. Chan Tao Fu N.W. Cheung N. Newman X. Liu

Ohmic contact

10.1557/proc-339-223

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Citations (3)

Shallow P⁺-N Junction Fabrication by Plasma Immersion Ion Implantation

MRS Proceedings (1991)

Carey A. Pico Xueyu Qian E.C. Jones M. A. Lieberman N.W. Cheung

Plasma-immersion ion implantation

Electron cyclotron resonance

10.1557/proc-223-115

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Citations (9)

Photoinduced diffusion of Ag in GexSe1−x glass

Applied Physics Letters (1985)

W. P. Leung N.W. Cheung A. R. Neureuther

Diffusion of Ag in GexSe1−x (x∼0.1) under UV light irradiation is studied using Rutherford backscattering spectrometry and microlithography techniques. The diffusion coefficient at 21 °C and 2 mW/cm2 is determined to be 2.7 nm2/s. The temperature dependence of the diffusivity follows an Arrhenius-type equation with an activation energy of 5.32 kcal/mole (0.23 eV) and a pre-exponent factor of 2.5×104 nm2/s. The reciprocity of irradiation intensity and exposure time with respect to the diffusion distance is confirmed. Specifically, the diffusivity is found to be directly proportional to the irradiation intensity.

Rutherford backscattering spectrometry

10.1063/1.95586

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Citations (17)

Optimization of Ge/C ratio for compensation of misfit strain in solid phase epitaxial growth of SiGe layers

Applied Physics Letters (1993)

Seongil Im J. Washburn R. Gronsky N.W. Cheung K. M. Yu

In order to study the strain-compensation effect by C atoms in solid phase epitaxial (SPE) growth of SiGe alloy layers, C sequential implantation was performed in [100] oriented Si substrates with various doses after high dose (5×1016/cm2) Ge implantation. When the nominal peak concentration of implanted C was over 0.55 at. % in the present sample series, misfit dislocation generation in the epitaxial layer was considerably suppressed. A SiGe alloy layer with 0.9 at. % C peak concentration under a 12 at. % Ge peak shows the greatest improved crystallinity compared to layers with smaller C peak concentrations. The experimental results, combined with a simple model calculation, indicate that the optimum Ge/C ratio for strain compensation is between 11 and 22.

Strain (injury)

10.1063/1.110419

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Citations (36)

Megavolt Bioron and Arsenic Implantation into Silicon

MRS Proceedings (1983)

P. F. Byrne N.W. Cheung Simon Tam C. Hu Yang Shib

10.1557/proc-27-253

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Citations (4)

GaN microcavities formed by laser lift-off and plasma etching

Materials Science and Engineering B (2002)

Robert Martin H.S. Kim Y. Cho P. R. Edwards I. M. Watson

Lift (data mining)

Plasma Etching

10.1016/s0921-5107(02)00042-9

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Citations (6)

Effect of antenna structures on charging damage in PIII

W.G. En N.W. Cheung

Antenna structures are shown to enhance charging damage in MOSFET devices during Plasma Immersion Ion Implantation (PIII). The antenna structure increases the total charge per pulse induced on the floating gate oxide, enhancing the charge by up to several orders of magnitude. Using a coupled analytical model of the plasma, device structure and substrate bias, the dependence of the antenna structure on the induced charge per pulse is found. From the simulation, the phase space of antenna ratio and charge per pulse is mapped into three regions: no charging damage, device degradation, and oxide failure. Experimental results using three different antenna ratios (5 k:1, 11 k:1, 44 k:1) correlate well with simulation results.

Plasma-immersion ion implantation

Antenna effect

10.1109/iit.1996.586572

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Citations (1)

Structural and optical quality of GaN/metal/Si heterostructures fabricated by excimer laser lift-off

Applied Physics Letters (1999)

William S. Wong Y. Cho E. R. Weber T. Sands K. M. Yu

Gallium nitride (GaN) thin films grown on sapphire substrates were successfully bonded and transferred onto Si substrates using a Pd–In metallic bond. After bonding, a single 600 mJ/cm2, 38 ns KrF (248 nm) excimer laser pulse was directed through the transparent sapphire followed by a low-temperature heat treatment to remove the substrate. Channeling-Rutherford backscattering measurements revealed the thickness of the defective interfacial region to be approximately 350 nm. The full width at half maximum, low-temperature (4 K), donor-bound exciton photoluminescence (PL) peak was larger by 25% on the exposed interfacial layer compared to the original GaN surface. Ion milling of the exposed interface to a depth of 400 nm was found to remove the interfacial layer and associated defects. The minimum channeling yield and PL linewidths from the exposed interface were found to be comparable to those obtained from the original GaN surface after ion milling.

10.1063/1.124861

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Citations (54)

Investigation of NEV Au⁺⁺ implanted silicon

Proceedings annual meeting Electron Microscopy Society of America (1990)

T. L. Alford N. David Theodore J. W. Mayer C.B. Carter N.W. Cheung

There has recently been increasing use of MeV ion beams for materials modification. When compared to more common lower, keV-energy implantation, MeV-ion irradiation has a broader variation in the type of damage along the ion path. This is because of the more significant difference between damage and range distributions in the case of MeV implants as opposed to keV implants. Previous works showed that MeV-implanted Si-ions react differently with various types of lattice damage in silicon; interactions range from simple point-defect annihilation to the formation of extended defects. Earlier investigations of Au implanted into previously amorphized silicon have observed Au segregation as a result of its being expelled from the recrystallizing amorphous layer during ion-beam irradiation. In this study, the interaction of MeV Au ++ atoms with the different types of damage produced along the MeV-ion beam path is investigated. Silicon (100) single crystal wafers were given a HF dip and were then mounted on a copper sample stage; the stage functions as a heat-sink. The stage together with the specimen was then placed in a Tandem ion-implanter. The specimens were implanted with gold; implant-energies varied from 1.8 - 4.4 MeV and fluences ranged between 0.1 - 10×10 16 Au ++ /cm 2 .

radiation damage

10.1017/s042482010017640x

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Citations (0)

Ion-cut silicon-on-insulator fabrication with plasma immersion ion implantation

Applied Physics Letters (1997)

Xiang Lü S. Sundar Kumar Iyer Chenming Hu N.W. Cheung Jing Min

We report the implementation of ion-cut silicon-on-insulator (SOI) wafer fabrication technique with plasma immersion ion implantation (PIII). The hydrogen implantation rate, which is independent of the wafer size, is considerably higher than that of conventional implantation. The simple PIII reactor setup and its compatibility with cluster-tools offer other ion-cut process optimization opportunities. The feasibility of the PIII ion-cut process is demonstrated by successful fabrication of SOI structures. The hydrogen plasma can be optimized so that only one ion species is dominant. The feasibility of performing ion-cut using helium PIII is also demonstrated.

Plasma-immersion ion implantation

10.1063/1.120127

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Citations (44)