In the last decade, we have seen rapid developments in metastable diamond synthesis by means of low-pressure chemical vapor deposition. Concurrently, a fast growing interest in diamond technology has emerged. This review discusses the various low-pressure growth methods of diamond films. Particular attention is paid to recent advances in the understanding of the mechanism of diamond nucleation and metastable growth. These advances are discussed in connection with the advances in diamond heteroepitaxy, which raises hopes that single crystalline diamond films are not far beyond reach. Modern surface science techniques applied to diamond study have played an essential role in these achievements and their contributions are discussed.

CVD diamond films: nucleation and growth

The Brenner hydrocarbon potential was extended recently to include interactions with silicon. This extended Brenner potential has now been improved by the fitting of bond order correction terms, and the introduction of an adjustable parameter into the angular function. The new potential gives an excellent description of small Si m H n molecules and radicals. Its treatment of the low index surfaces of silicon and β-SiC is also significantly improved, although the recently proposed non-dimerized structure for the silicon terminated (001) surface of β-SiC is not described properly. Calculations of the chemisorption of C2H2 and CH3 onto the (001) surfaces of silicon and β-SiC using this improved potential are reported. Also presented are some initial results of molecular dynamics simulations of the Si(111) 7 × 7:CH3 and hydrogenated Si(001) 2 × 1:C2H2 chemisorption systems.

Improved empirical interatomic potential for C—Si—H systems

From time immemorial, diamond attracted a special attention not only as a precious gemstone but also as an application material due to its unique and unsurpassed properties. Interest in diamond thi...

Review of advances in diamond thin film synthesis

Electron energy loss spectroscopy, in the regime corresponding to losses < 500 meV, is now routinely exploited for the characterisation of material surfaces. Recent instrumental advances and improvements in data analysis enable the study of widely different materials and contributions to the solution of surface and near-surface problems, many of which have a technological importance in fields as diverse as semiconductor devices, molecular sensors and heterogeneous catalysis.

High resolution electron energy loss spectroscopy

Behavior of hydride species on Si surface during methane plasma irradiation investigated by in-situ infrared spectroscopy

The reaction of atomic hydrogen with the C2H2-covered Si surface was studied using high-resolution electron-energy-loss spectroscopy (HREELS), thermal-desorption mass spectrometry (TDMS), and low-energy electron diffraction. We found that atomic hydrogen broke up the carbon-carbon bond in C2H2 and the Si-Si dimers on the Si surface, which led to the formation of C-H and Si-H bonds, respectively. When the C2H2-covered Si(100) surface was exposed to a filament-activated H-2/CH4 mixture, HREELS showed that the C-H stretching signal grew at the expense of the Si-H stretching signal. This observation was consistent with the replacement of the Si-H bond by - CH3, possibly following hydrogen abstraction from the Si-H bond by atomic hydrogen. TDMS analysis showed significant desorption of atomic hydrogen at both 650 and 750 K and a little desorption of CH2 and CH3 only at 650 K, although HREELS remained unchanged with annealing temperature. This showed that part of the hydrocarbon species on the Si surface existed as a stable network of hydrocarbon, which possibly was the initial stage of diamond formation on Si.

Zhiqing Gao

Papers

Role of hydrogen in the initial stage of diamond heteroepitaxy on silicon.