Mosaic growth of diamond: a study of homoepitaxial flame deposition and etching of {001}-oriented diamond layers

Abstract

This study describes homoepitaxial growth and etch phenomena observed on cubic diamond faces as obtained by the application of an acetylene-oxygen combustion flame. It is demonstrated that flame etching of the diamond substrates prior to growth decreases the number of crystallographic imperfections in the diamond layers especially at the edges. This enables a more uniform distributed step generation by the large number of individual dislocations present in the used natural type IIa diamond substrates. Due to this improvement it appears possible to grow one single crystal diamond layer on top of several closely spaced, well-aligned natural diamond substrates. In the present work the overgrowth of a three-piece mosaic structure with gaps along (100) as well as along (110) is reported for the first time. The single crystal nature of this flame-deposited diamond layer could be confirmed by the observation of continuous growth step patterns at the surface across the joint regions. The widths of the gaps between the substrates in the original mosaic structure varied from 7 to 25 ~m, which is more than an order of magnitude larger than the gaps along (100) in two-piece mosaic structures, of which the single crystal overgrowth by HFCVD was previously reported. Comparison of micro-Raman spectra obtained from the joint regions with those from other parts of the overgrown mosaics discussed in the present work, show a larger FWHM of the diamond peak in case of a (110) joint and a shift of the peak position to higher wave numbers in case of a (100) joint.

Identification of Synthetic Diamond Grown Using Chemical Vapor Deposition (CVD)

“…Beginning in the early 1990s, however, a number of research groups published studies of the growth of somewhat thicker CVD synthetic diamond. For example, researchers at Nijmegen University, the Netherlands, reported flame and hot filament growth of layers up to 0.5 mm thick (Janssen et al, 1990(Janssen et al, , 1991Schermer et al, 1994Schermer et al, , 1996. In the U.S., Crystallume (Landstrass et al, 1993;Plano et al, 1994) used microwave CVD to produce layers of similar thickness, and Badzian and Badzian (1993) described a layer of single-crystal synthetic diamond that was 1.2 mm thick.…”

Influence of nitrogen addition on oxyacetylene flame chemical vapor deposition of diamond as studied by solid state techniques and gas phase diagnostics

“…51,52 As a result, the nuclei develop into hemispherical structures that are bounded by ͕001͖ facets with their normals perpendicular to the surface of the structure. In the nucleation phase, nuclei are formed that are bounded by ͕111͖ and ͕001͖ facets and have a random orientation.…”

Coessential-connection by microwave plasma chemical vapor deposition: a common process towards wafer scale single crystal diamond

“…This so called "two step" process was tried, with short-tome HFCVD diamond deposition for bridging the gaps between the substrates, followed by high-rate growth using oxygen combustion flame method to deposit a thicker film (~250 μm) [37]. Schermer et al [38] studied carefully the surface morphology and the structure of joint part, the junction between elements of mosaics by SEM and Raman spectroscopy. In the same year, Posthill et al [39,40] also successfully prepared mosaic diamond by the similar approach, but using Ni coating to bond the substrates in one body and performing epitaxial growth by RFCVD.…”