Homoepitaxy diamond

Several researchers have reported successful deposition of homoepitaxial diamond films on natural as well as HPHT diamond substrates (e.g., 101-104). 

Figure 8.1. STM images of a homoepitaxial diamond layer surface deposited on single crystal diamond (100) surface [138].

The (100), (110), and (HI) surfaces of homoepitaxial diamond layers, grown on type Ila diamonds by HFCVD, were observed by an atmospheric AFM in Ref [145]. On the (100) surface, there was indication of the presence of 2 x 1 reconstructed dimers, though no atomic image was observed. Other surfaces were found to be quite rough. A STM study of (111) faces on polycrystalline... 

A homoepitaxial diamond layer deposited by MPCVD on a diamond Ib (111) surface was studied by STM [147]. See also Ref. [142]. The H-terminated (111) surface had a 1 x 1 structure with C-H bonds vertically sticking out of the surface. 

The electrical properties of single crystal diamond will be useful to study those of heteroepitaxial diamond films. As a reference. Figures 13.1 (a)-(c) show the resistivity, mobility, and carrier density of single crystal diamond as a function of temperature [107]. Figures 13.2 (a) and (b) are the resistivity and mobility as a function of the carrier density. A more thorough study on B-doped homoepitaxial diamond is presented in Ref. [416], where AFM observation of the layer surface. Hall measurements at different temperatures, and other data are presented. 

Small amounts of well crystallized diamond were found after hydrothermal treatment of P-SiC powder at 700-750°C in the presence of diamond seed [55]. After removing silica and nondiamond carbon, small (<3pm) carbon particles of predominantly octahedral shape, thus being probably diamond, were found. They were attached to the surfaces of the single crystal seed but could be removed by intense ultrasonic treatment. Tetrahedral hillocks of etch pits appeared on the seed diamond surfaces. The hillocks always showed a faceted structure and sometimes common orientation, as expected for homoepitaxial diamond growth. 

Muret, P., Mortet V., Haenen, K., and Teraji, T. (2010) Hall hole mobility in boron-doped homoepitaxial diamond. Phys. Rev. B, 81(20), 205203. 

Y Kuang, N Lee, A Badzian, TT Tsong, T Badzian, C Chen. Study of antiphase boundaries and local 3X1 configuration on the (001) surface of homoepitaxial diamond films by STEM. Diamond Relat Mater, 4 1371, 1995. 

S Koizumi, M Kamo, Y Sato, H Ozaki, T Inuzuka. Growth and characterization of phosphorus doped 111 homoepitaxial diamond thin films. Appl Phys Lett 71 1065, 1997. 

In spite of the importance of single-crystal diamond electrodes, the number of reports on their electrochemistry [1-7] is still small, much smaller than that for polycrystalline diamond electrodes. The main reason for this situation is the limited availability of the single-crystal diamond samples. Generally, in the case of CVD film preparation, the area of the polycrystalline diamond thin film depends on the capability of the deposition apparatus (e.g., power), because large silicon wafers can be used as substrates. In contrast, in the case of single-crystal homoepitaxial diamond thin films, the... 

Differences in the surface conductivity with surface termination of diamond can be applied to the nanolithographic modification of diamond surfaces by use of atomic force microscopy (AFM) techniques [50-52]. Modification can be carried out by applying an electrical bias to the sample surface via a conductive cantilever tip, e.g., Au coated Si (Fig. 8.8). Surface modification using such an AFM technique is relatively general, and has been achieved for semiconductor materials such as Si [53], GaAs [54] and metals such as Ti [55]. Recently, Tachiki et al. and Kondo et al. have applied this technique to single-crystal homoepitaxial diamond thin films, undoped and boron-doped, respectively. In this section, we discuss the properties of diamond surfaces modified via AFM techniques and possible applications. 

Fig. 8.8. A schematic drawing of nanolithography on homoepitaxial diamond with a conductive AFM tip.

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