On epitaxial growth of diamond films on (100) silicon substrates

Abstract

We have investigated characteristics of polycrystalline diamond thin films formed by plasma-enhanced chemical vapor deposition method on silicon substrates using Raman spectroscopy, analytical and high-resolution transmission electron microscopy techniques. Grains with average size 1 μm in diameter were observed in these films. The Raman spectra from these films contain the strongest peak at 1335 cm−1, providing the characteristic signature for sp3 (diamond) bonding. The broad peak centered around 1550 cm−1 is believed to be due to some graphitic bonding. From detailed high-resolution images and microdiffraction, films were characterized to be cubic diamond with a lattice parameter of 3.56 Å. Diamond crystallites with fivefold external morphologies were also observed. The large crystallites in the films exhibited preferential texture in 〈011〉 type orientations. These crystallites were found to be twinned in {111} planes. The large 〈011〉 crystallites exhibited matching in {111} or {200} lattice planes of diamond with {022} planes of silicon. This is in agreement with our previous work on the growth of Ni on MgO, which showed that textured growth can occur by matching a set of lattice planes in the absence of matching of lattice constants.

Anisotropy analysis of the surface energy of diamond cubic crystals

“…Similarly, the anisotropy of strain energy can supply an additional driving force for abnormal grain growth, as we have discussed previously, 8 -13 and the anisotropy of surface and interface energy can supply an additional driving force for abnormal grain growth to result in a preferred orientation or texture in thin films. This behaviour with surface-energy-driven secondary grain growth (SEDSGG) has been observed in Au, 14 Cu, 15 Al, 16,17 Si, 18 -20 Ge 21 -23 and diamond 24,25 films and leads to grains much larger than film thickness and grains with uniform crystallographic (111) and (211) textures.…”

“…This is consistent with experimental results. The (111) texture has been observed in ultrathin Si, 18 -20 Ge 21 -23 and diamond 24,25 films. The (211) texture has been observed also by Yonehara et al in ultrathin Ge films.…”

An optical emission spectroscopy study of the plasma generated in the DC HF CVD nucleation of diamond

“…At 0 V, the spectra exhibit the peaks at 1210, 1300, 1350, and 1550 cm À1 which are attributed to the sp 2 carbon phase [40,41]. At 5 V, we observed two bands centered at 1330 and 1555 cm À1 , indicating the formation of DLC type [42][43][44]. From Fig.…”

Valence electron structure analysis of epitaxial growth of diamond (100) film on Si and c-BN substrate

“…The reason why the diamond (1 0 0) film could not grow directly on the (1 0 0) Si substrate [21][22][23] is that the REDD between diamond (1 0 0) plane and Si (1 0 0) plane is too large ðDr Cð1 0 0Þ=Sið1 0 0Þ ¼ 1:6679Þ to satisfy continuity of electron density across the interface.…”

“…The observations made under the scanning electron microscope reveal oriented cubic nucleations are not only oriented to one another, but also to the highly faceted local epitaxy crystals at an angle 451 off of the silicon substrate cleavage plane. Nanayan et al [22] used plasma-enhanced chemical vapor deposition method to prepare diamond film on the (1 0 0)-oriented Si substrate, but a polycrystalline diamond film was obtained. Although a local epitaxy diamond film was obtained by Williams and Glass [23], it was most likely a limited epitaxial growth on silicon carbide.…”