Electrophysical properties of diamond films deposited on silicon substrates by hfcvd method

Abstract

Electrically conductive diamond films were deposited on n-type Si(100) substrates by the hot filament chemical vapor deposition (HFCVD) method using a hydrogen–methanol gas mixture with ammonia addition. In contrast to conventional approaches, film growth was performed without preliminary hydrogen etching of the silicon surface, which simplified the technological process. The deposition conditions were optimized to suppress the formation of non-diamond carbon phases and improve film quality. Raman spectroscopy revealed a pronounced diamond-related peak at 1333 cm⁻¹ with a relatively small contribution of sp²-bonded carbon, indicating the predominance of the diamond phase in the deposited films. The films had thicknesses of 2.2–2.8 μm and were grown at a rate of 0.2-0.3 μm h⁻¹. The electrophysical properties were investigated in the temperature range of 300–500 K using Hall-effect measurements. The carrier concentration increased exponentially with temperature, while the carrier mobility decreased due to enhanced phonon scattering, confirming the semiconducting nature of the deposited films. The observed temperature dependences of carrier concentration, mobility, and resistivity were found to be consistent with the behavior expected for semiconductor materials. The results demonstrate that high-temperature HFCVD growth without preliminary hydrogen etching can produce diamond films with satisfactory structural quality and stable electrical characteristics, making them promising for potential electronic and optoelectronic applications.

Keywords: CVD technology, diamond film, silicon substrate, Raman spectra, charge carrier mobility, temperature dependence.