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MATERIALS RESEARCH

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Homoepitaxial (111) diamond grown by temperature-controlled chemical vapor deposition Mikka Nishitani-Gamo and Isao Sakaguchi Core Research for Evolutional Science and Technology (CREST) of Japan Science and Technology Corporation (JST), c/o National Institute for Research in Inorganic Materials (NIRIM), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan

Tomohide Takami, Katsunori Suzuki, and Isao Kusunoki Core Research for Evolutional Science and Technology (CREST) of Japan Science and Technology Corporation (JST) and Research Institute for Scientific Measurements (RISM), Tohoku University, 2-1-1 Katahira, Sendai 980-8577, Japan

Toshihiro Andoa) Core Research for Evolutional Science and Technology (CREST) of Japan Science and Technology Corporation (JST), c/o NIRIM, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan (Received 17 November 1998; accepted 8 June 1999)

We investigated the growth of high-quality homoepitaxial diamond on the (111) face in a microwave-assisted plasma chemical-vapor-deposition system incorporating an individual substrate heating/cooling device. The grown diamond films were characterized by scanning electron microscopy, reflection high-energy electron diffraction, atomic force microscopy, confocal micro-Raman spectroscopy, and secondary ion mass spectrometry. The (111) diamond films show a tendency to incorporate a significant amount of hydrogen during chemical-vapor-deposition growth. Hydrogen incorporation degrades the crystal quality and surface smoothness. The amount of incorporated hydrogen decreases with the decrease in deposition temperature. We have shown that the crystal quality and surface smoothness of homoepitaxial diamond strongly depend on the substrate temperature. Independent control of the substrate temperature and incident microwave power is essential for high-quality diamond homoepitaxy.

I. INTRODUCTION

Microwave-assisted plasma chemical vapor deposition (MPCVD) is widely used for diamond synthesis from the vapor phase. Diamond and related materials have many potential applications as wide band-gap semiconductors, optical devices, cutting tools, heat sinks, and fieldemission devices. Thin polycrystalline diamond films can be grown on foreign substrates, but their uses in electronics are limited by grain boundaries and defects. Only single-crystal diamond, which can be grown homoepitaxially on a single-crystal diamond substrate by MPCVD, can meet the demands of high performance electronics. Although many reports have described the homoepitaxial growth of (001) diamond,1–4 optimal growth conditions have not yet been determined, and the mechanism for this reaction remains unclear. Moreover, fewer studies have described high-quality homoepitaxial diamond growth on the (111) surface. It is more difficult

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Address all correspondence to this author. e-mail: [email protected]

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http://journals.cambridge.org

J. Mater. Res., Vol. 14, No. 9, Sep 1999 Downloaded: 14 Mar 2015

to grow a high-quality homoepitaxial diamond on the (111) fac