Influence of gas phase parameters on the deposition kinetics and morphology of thin diamond films deposited by HFCVD and MWCVD technique

Abstract

This paper reports on the deposition of thin diamond films with rates of more than 15 μm/h with the Hot Filament CVD (HFCVD) technique. We compare in some detail deposition kinetics of films from different source gases. Using different oxygen-containing species like methanol, acetone, DMP and a CH 4/H 2/O 2 gas mixture, we studied the influence of the carbon to oxygen ratio in the source material as well as the effect of free and bonded oxygen addition to the gas phase. On the other hand, deposition parameters, especially the filament to substrate distance, are found to strongly affect all the film parameters investigated. High deposition rates were obtained using low filament to substrate distances ( d F ⩽1mm). The second part of this paper reports on the deposition of diamond using Micro Wave Chemical Vapour Deposition (MWCVD). Using oxygen-containing compounds at high carbon concentration in the gas phase (C/H⩾ 20%), we succeeded in depositing diamond at low substrate temperatures (⩽400 °C). We will report on the deposition of high quality diamond films without the addition of molecular hydrogen to the gas phase using only methanol.