Scanning Tunneling Microscopy Studies of Temperature-Dependent Etching of Diamond (100) by Atomic Hydrogen

Stallcup, Richard E.; Pérez, Jose

doi:10.1103/physrevlett.86.3368

Cited by 33 publications

(32 citation statements)

References 16 publications

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“…This fact would imply that etching must stop after 6 min, which seems very unlikely. In addition, features that are commonly attributed to surface etching, like terraces becoming filled with vacancies and pits, or steps becoming rougher with longer exposures, are never observed on any of the surfaces [36][37][38][39][40]. Therefore, we conclude that, in general, etching is not the source of the morphological and structural changes observed on vicinal Si(0 0 1) surfaces.…”

Section: Etchingmentioning

confidence: 63%

Step structure and surface morphology of hydrogen-terminated silicon: (001) to (114)

Laracuente

Whitman

2003

Surface Science

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Section: Etchingmentioning

confidence: 63%

Step structure and surface morphology of hydrogen-terminated silicon: (001) to (114)

Laracuente

Whitman

2003

Surface Science

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“…We have successfully produced 5-carat single crystal (dimensions, 7 ϫ 8 ϫ 5 mm) after an Ϸ10-timeslonger regrowth from a 0.3-mm-thick seed, but it was brown in color and had a crack on the {111} face. This phenomenon may be due to initial atomic hydrogen etching or a hot edge that will promote a darker, discontinuous interface during regrowth, twin formation, or internal stresses (15,18). The sharp {111} cracking implies that our CVD diamond is a single crystal.…”

mentioning

confidence: 99%

Very high growth rate chemical vapor deposition of single-crystal diamond

Yan

Vohra

Mao

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

235

109

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Diamond possesses extraordinary material properties, a result that has given rise to a broad range of scientific and technological applications. This study reports the successful production of highquality single-crystal diamond with microwave plasma chemical vapor deposition (MPCVD) techniques. The diamond single crystals have smooth, transparent surfaces and other characteristics identical to that of high-pressure, high-temperature synthetic diamond. In addition, the crystals can be produced at growth rates from 50 to 150 m͞h, which is up to 2 orders of magnitude higher than standard processes for making polycrystalline MPCVD diamond. This high-quality single-crystal MPCVD diamond may find numerous applications in electronic devices as high-strength windows and in a new generation of high-pressure instruments requiring large single-crystal anvils. Diamond produced by low-pressure microwave plasma (MP) chemical vapor deposition (CVD) is the most promising technology for producing low-cost and high-quality large diamond (1, 2). Nevertheless, the widespread use of MPCVD diamond in many applications has not been successful due to the existence of grain boundaries of polycrystalline diamond that are produced and slow growth rates, typically 1 m͞h (1-7). Diamond's strong covalent bonds and rigid structure (8) give rise to its unique properties. Diamond is the hardest and stiffest material known, has the highest room-temperature thermal conductivity and one of the lowest thermal expansion of known materials, and is radiation-hard and chemically inert to most acidic and basic reagents. Due to the high cost, limited size, and uneasily controlled impurities of natural and synthetic highpressure, high-temperature (HPHT) diamond, the applications of diamond have in fact been limited in comparison to its great potential (8). Thus, CVD diamond is the most promising avenue available for synthetic diamond. The major CVD diamondcoating techniques are the hot-filament, radio-frequency plasma, MP, and arcjet-torch methods (8, 9). Comparing these techniques, MPCVD-reactor methods provide stable conditions, reproducible sample quality, and reasonable cost (8, 9). In fact, steady progress in MPCVD synthesis techniques has made it possible to manufacture high-quality polycrystalline CVDdiamond optical components (4, 10), but this polycrystalline material consists of a patchwork of tiny crystals welded to one another along misaligned grain boundaries, which block the flow of current (10-12). The major disadvantage of MPCVD using 12.2 cm͞2.54 GHz for plasma generation is the lower growth rate, typically 1 m͞h (1-7) compared with arcjet torches; moreover at several hundred micrometers per hour (13), the plasma tends to concentrate at tips and edges (9, 13). Here we show that MPCVD diamond can be produced as high-quality and high growth rate (50-150 m depending on stage design and methane concentration) single crystals for a variety of purposes including the enlargement of anvils (14) for compressing large samples at ultrahigh pressures....

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“…This is in contrast to high-resolution STM images of the hydrogenated diamond 6,15-18 and hydrogen-free diamond surfaces. [19][20][21] STM images of the hydrogenated diamond ͑100͒ surface could not separate the hydrogen atoms, which are clearly resolved in the NC-AFM image presented here. On the clean diamond ͑100͒ surface, individual C-C dimers could not be seen with the STM whereas they are clearly visible with the NC-AFM as demonstrated in this work.…”

mentioning

confidence: 71%

Atomic-resolution imaging of clean and hydrogen-terminated C(100)-(2×1)diamond surfaces using noncontact AFM

et al. 2010

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High-purity, type IIa diamond is investigated by noncontact atomic force microscopy ͑NC-AFM͒. We present atomic-resolution images of both the electrically conducting hydrogen-terminated C͑100͒-͑2 ϫ 1͒ :H surface and the insulating C͑100͒-͑2 ϫ 1͒ surface. For the hydrogen-terminated surface, a nearly square unit cell is imaged. In contrast to previous scanning tunneling microscopy experiments, NC-AFM imaging allows both hydrogen atoms within the unit cell to be resolved individually, indicating a symmetric dimer alignment. Upon removing the surface hydrogen, the diamond sample becomes insulating. We present atomic-resolution images, revealing individual C-C dimers. Our results provide real-space experimental evidence for a ͑2 ϫ 1͒ dimer reconstruction of the truly insulating C͑100͒ surface. Hydrogenated and clean diamond surfaces ͓see model in Figs. 1͑a͒ and 1͑b͔͒ have attracted considerable interest in recent years, motivated by the unique electronic, thermal, mechanical, and optical properties of diamond, 1-3 which makes it suitable for high power laser and gyrotron applications or field-effect transistors. 4 Most of the diamond samples, both natural diamond and artificial chemical-vapor deposition ͑CVD͒ diamond, have a low impurity concentration and are insulating. For example, so-called type IIa diamond exhibits an impurity concentration of less than 1 ppm. Therefore, type IIa diamond is not sufficiently conducting for scanning tunneling microscopy ͑STM͒ imaging unless a water layer is present. 5,6 Thus, atomic force microscopy ͑AFM͒ appears to be the ideal tool for a high-resolution study of the diamond surface. Highest resolution has recently been demonstrated for bare dielectric surfaces 7-9 and molecules on insulators, 10-13 including submolecular resolution of a pentacene molecule at low temperature. 14 However, despite many attempts, atomic-scale AFM imaging of diamond surfaces has not been successful so far. To progress further in our understanding of diamond, a detailed characterization of its surface structure is necessary.In this Rapid Communication, we present atomically resolved noncontact AFM ͑NC-AFM͒ images that reveal the individual hydrogen atoms on the hydrogenated diamond ͑100͒ surface, and the C-C dimers on the hydrogen-free diamond ͑100͒ surface. This is in contrast to high-resolution STM images of the hydrogenated diamond 6,15-18 and hydrogen-free diamond surfaces.19-21 STM images of the hydrogenated diamond ͑100͒ surface could not separate the hydrogen atoms, which are clearly resolved in the NC-AFM image presented here. On the clean diamond ͑100͒ surface, individual C-C dimers could not be seen with the STM whereas they are clearly visible with the NC-AFM as demonstrated in this work. As a matter of fact, NC-AFM offers greatly enhanced resolution compared to STM for both the hydrogenated and clean diamond surfaces.

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Scanning Tunneling Microscopy Studies of Temperature-Dependent Etching of Diamond (100) by Atomic Hydrogen

Cited by 33 publications

References 16 publications

Step structure and surface morphology of hydrogen-terminated silicon: (001) to (114)

Step structure and surface morphology of hydrogen-terminated silicon: (001) to (114)

Very high growth rate chemical vapor deposition of single-crystal diamond

Atomic-resolution imaging of clean and hydrogen-terminated C(100)-(2×1)diamond surfaces using noncontact AFM

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