PECVD technologies assisted with millimeter waves

Abstract

Gas discharges supported by millimeter wave beams generated by gyrotron are considered. Such discharges produce super high density plasma. Application of these discharges in the PECVD (plasma enhances chemical vapour deposition) technologies allow to increase the rate of activation of the gas medium sufficiently as compared with traditional microwave based reactors in which plasma is generated by radiation of 2.45 GHz and 0.915 GHz frequencies. The continuous gas discharge generated by crossing millimeter-wave beams is used for CVD diamond film deposition. The paper demonstrates the potentials of a plasma CVD reactor with millimeter-waves taking a novel PECVD reactor based on the 10kW/30 GHz gyrotron. In the developed reactor the following conditions of the polycrystalline diamond coating process are carried out simultaneously: the deposition rate is about 10 mum/h, the size of diamond film area is about 100 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . As a result the diamond films with high thermal conductivity and optical transparency are grown. The continuous gas discharge generated by single millimeter wave beam at ECR conditions can be used for CVD deposition of nanocrystalline silicon films with isotope- modified composition ( <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">28</sup> Si- <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">30</sup> Si-isotope enriched films) from SiF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> precursor. Such silicon films have high thermal conductivity. The presentation demonstrates the first results of growth and characterization of such films using traditional inductively coupled plasma. The PECVD reactor based on 30GHz gyrotron for plasma production at ECR conditions is now under construction.