Effect of Annealing and Microwave Hydrogen Plasma Treatment on Structural, Chemical, and Electronic Properties of Ion Irradiated Diamond Films

ABSTRACTIn the present study we correlate between the secondary electron emission (SEE) of variously treated Xe+ ion-damaged diamond films and their bonding structure in the near-surface region as identified by near edge X-ray absorption fine structure (NEXAFS) spectroscopy and X-ray photoelectron spectroscopy. The 50 keV Xe+ ion bombardment of hydrogenated polycrystalline diamond films to a dose of 2×1015 cm−2 results in the transformation of near-surface diamond to sp2-bonded amorphous carbon, increased oxygen adsorption, shift of the electron affinity from negative to positive, and strong degradation of its electron emission properties, although it does not induce a pronounced depletion of hydrogen. Exposure of the ion-bombarded films to microwave (MW) hydrogen plasma treatment for 30 min produces negative electron affinity diamond surfaces, but only partially regenerates SEE properties, retains some imperfection in the near-surface atomic layers, as determined by NEXAFS, and the concentration of oxygen remains relatively high. Subsequent annealing to 610 °C produces oxygen-free diamond films and somewhat increases their SEE. Annealing to 1000 °C results in desorption of the surface hydrogen, formation of a positive electron affinity surfaces and drastically degrades their electron emission properties. Prolonged, up to three hours MW hydrogen plasma treatment of as-implanted diamond films gradually improves the crystal quality and results in further increase of SEE intensity. This treatment does not, however, substantially reduce the concentration of oxygen in the previously damaged diamond, indicating its bulk diffusion during or after ion bombardment. To fully recover electron emission properties it is necessary to both remove the defects and hydrogenate the diamond surfaces.

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Effect of hydrogen plasma treatment on secondary electron emission properties of polycrystalline diamond films

Vacuum ◽

10.1016/j.vacuum.2019.109046 ◽

2020 ◽

Vol 172 ◽

pp. 109046 ◽

Cited By ~ 2

Author(s):

Kongting Wei ◽

Jie Li ◽

Biye Liu ◽

Rongrong Wu ◽

Qiang Wei ◽

...

Keyword(s):

Plasma Treatment ◽

Electron Emission ◽

Secondary Electron ◽

Hydrogen Plasma ◽

Secondary Electron Emission ◽

Diamond Films ◽

Polycrystalline Diamond ◽

Emission Properties

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THE INFLUENCE OF ION IRRADIATION ON THE ABSOLUTE QUANTUM PHOTOYIELD OF DIAMOND FILMS STUDIED BY ELECTRON SPECTROSCOPY AND H+ PHOTODESORPTION

Surface Review and Letters ◽

10.1142/s0218625x00000440 ◽

2000 ◽

Vol 07 (04) ◽

pp. 455-462 ◽

Cited By ~ 3

Author(s):

A. LAIKHTMAN ◽

A. HOFFMAN

Keyword(s):

Photoelectron Spectroscopy ◽

Electron Spectroscopy ◽

Ion Irradiation ◽

Hydrogen Plasma ◽

Secondary Electron Emission ◽

Diamond Films ◽

Ion Bombardment ◽

Partial Recovery ◽

Near Surface ◽

Absolute Quantum

In this study we report on absolute quantum photoyield (QPY) measurements from well-defined defective diamond surfaces in the 140–200 nm spectral range. The effect of defects in polycrystalline diamond films on their photoemission properties is studied by intentionally introducing damage using room temperature 30 keV Xe + ion bombardment to doses ranging from 2×1013 to 2×1015 ions/cm 2. Ion bombardment results in a drastic degradation of the QPY, to less than 1% at 140 nm, even at the lowest implantation dose compared to ~11.5% measured for the unimplanted diamond film. Analysis of the ion-damaged diamond films is performed by photon-stimulated ion desorption (PSID) measurements of H +, high resolution C(KLL) Auger electron spectroscopy and X-ray photoelectron spectroscopy. These measurements reveal that the decay in photoemission is due to the gradual formation of nondiamond carbon in the near-surface region. This damage leads to a change of the electron affinity from negative to positive, as determined by secondary electron emission measurements. PSID measurements reveal that the ion-bombarded diamond films remain hydrogen-terminated. MW hydrogen plasma treatment results in complete regeneration of the photoemission properties for diamond films implanted to Xe + doses of up to 2×1014 cm -2; only partial recovery was obtained for films irradiated with a higher ion dose.

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Enhancement of secondary electron emission by annealing and microwave hydrogen plasma treatment of ion-beam-damaged diamond films

Journal of Applied Physics ◽

10.1063/1.1432479 ◽

2002 ◽

Vol 91 (4) ◽

pp. 2481-2486 ◽

Cited By ~ 6

Author(s):

A. Laikhtman ◽

A. Hoffman

Keyword(s):

Plasma Treatment ◽

Electron Emission ◽

Secondary Electron ◽

Ion Beam ◽

Hydrogen Plasma ◽

Secondary Electron Emission ◽

Diamond Films

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Electronic Structure of Polycrystalline PECVD Diamond Surfaces

MRS Proceedings ◽

10.1557/proc-416-133 ◽

1995 ◽

Vol 416 ◽

Cited By ~ 3

Author(s):

T. P. Humphreys ◽

D. P. Malta ◽

R. E. Thomas ◽

J. B. Posthill ◽

M. J. Mantini ◽

...

Keyword(s):

Electronic Structure ◽

Electron Emission ◽

Hydrogen Plasma ◽

High Vacuum ◽

Diamond Films ◽

Chemical Vapor ◽

Polycrystalline Diamond ◽

Low Energy ◽

Diamond Surfaces ◽

Single Crystal Diamond

ABSTRACTUltraviolet and X-ray photoelectron spectroscopy techniques have been employed in a preliminary study of the electronic structure of polycrystalline diamond films that have been grown on Si substrates by if-plasma enhanced chemical vapor deposition using water/ethanol growth chemistries. In particular, polycrystalline diamond films with distinctly different surface morphologies and Raman scattering characteristics have been investigated. Corresponding ultraviolet photoemission spectra from air-exposed samples have shown the presence of a prominent low-energy secondary electron emission peak indicative of a negative electron affinity (NEA) surface. Chemical stability of the polycrystalline diamond NEA surface has been demonstrated following conventional acid cleans and hydrogen plasma processing. In contrast, an oxygen (20%)/Ar plasma exposure has been shown to extinguish the photoemission of low-energy secondary electrons and remove the NEA. However, by employing a high-temperature anneal at 750 °C for 15 min in ultra-high vacuum the NEA surface can be restored. Compared to NEA single crystal diamond surfaces the photoexcited low-energy electron emission from chemical vapor deposited polycrystalline diamond films is more robust.

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Electron emission properties of laser pulsed GaAs negative electron affinity photocathodes

Journal of Vacuum Science & Technology B Microelectronics Processing and Phenomena ◽

10.1116/1.585172 ◽

1990 ◽

Vol 8 (6) ◽

pp. 1853 ◽

Cited By ~ 10

Author(s):

Colin A. Sanford

Keyword(s):

Electron Affinity ◽

Electron Emission ◽

Negative Electron Affinity ◽

Emission Properties

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Etching effects of hydrogen plasma treatment on diamond surfaces

Surface and Coatings Technology ◽

10.1016/j.surfcoat.2019.02.007 ◽

2019 ◽

Vol 363 ◽

pp. 12-17 ◽

Cited By ~ 1

Author(s):

He Jiang ◽

Fengbin Liu ◽

Hongjuan Yan ◽

Lina Si ◽

Zhaoliang Dou

Keyword(s):

Plasma Treatment ◽

Hydrogen Plasma ◽

Diamond Surfaces

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Properties of Surface States on GaN and Related Compounds and Their Passivation by Dielectric Films

MRS Proceedings ◽

10.1557/proc-743-l2.6 ◽

2002 ◽

Vol 743 ◽

Cited By ~ 1

Author(s):

Hideki Hasegawa ◽

Tamotsu Hashizume

Keyword(s):

Plasma Treatment ◽

Surface State ◽

Surface Passivation ◽

Hydrogen Plasma ◽

Surface States ◽

Ex Situ ◽

Near Surface ◽

Ecr Plasma ◽

Good Surface ◽

Donor States

ABSTRACTThis paper reviews the authors′ recent efforts to clarify the properties of electronic states near surfaces of GaN and AlGaN by using variousin-situandex-situcharacterization techniques, including UHV contact-less C-V, photoluminescence surface state spectroscopy (PLS3), cathode luminescence in-depth spectroscopy (CLIS),and gateless FET techniques that have been developed by the authors’ group.As a result, a model including a U-shaped surface state continuum, having a particular charge neutrality level, combined with frequent appearance of near-surface N-vacancy related deep donor states having a discrete level at Ec - 0.37eV is proposed as a unified model that can explain large gate leakage currents and current collapse in AlGaN/GaN HFETs. Hydrogen plasma treatment and SiO2deposition increase N-vacancy related deep donors. Reasonably good surface passivation can be achieved by ECR-plasma SiNx films and by ECR-plasma oxidized Al2O3films both combined with ECR N2plasma treatment.

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