Tungsten deposition by dual-frequency inductively coupled plasma-assisted CVD

A new inductive plasma reactor has been developed for coating complex, thre e-dimensional parts using the plasma-enhanced chemical vapour deposition (P ECVD) technique. In order to control independently the temperature of the p arts to be treated, induction heating has been adapted to an inductively co upled plasma CVD reactor. Design of low-pass and high-pass filters has been made in order to prevent interference of the two frequencies: 13.56 MHz fo r plasma generation and 150 kHz for heating. Ion-current densities have bee n measured over a large pressure range: large ionic current can be obtained at an optimum pressure of 13 Pa (100 mtorr). Preliminary deposition tests of tungsten from WF6/H-2 have been made. It has been found that the H-2/WF6 flow rate ratio is strongly related to the microstructure and crystal stru cture. Tungsten films have a columnar microstructure. Lack of contamination by fluorine was verified. (C) 1999 Elsevier Science S.A. All rights reserv ed.