THE DIAMOND GROWTH – CVD ASSISTED BY HOT FILAMENT IN SILICON SUBSTRATE IN 80 cm 2 AREAS

Abstract

Nowadays, the diamond grown by chemical vapor deposition (CVD) is seen economically as one of the most interesting materials, due to its vast application, mainly in short-term, resulting from diamond’s unique properties. Its applications reach many technological areas, standing out the mechanics area due to possibilities use as cutting tools, tribological layers in automobiles and aeronautical engines, heat sinks, surfaces protection for aggressive environments and abrasive special devices which also add applications in biological areas. The largest obstacle for these applications is the high cost of diamond films production if compared commercially with other alternative materials. So, the area and the growth rate increasing is a solution for the costs reduction in the diamond production. The CVD diamond samples used in this work had been grown in a big reactor, for growth in big areas, by the hot filament chemical vapor deposition technique (HFCVD). The precursory mixture of 2% of methane in hydrogen was maintained by a of 50 mbar pressure for a E2M8 - Boc Edwards vacuum pump. The substrate used in the growths was silicon (100) with 100mm of diameter. The growth temperature was maintained in (800 ± 20) °C and the growth time was changeable until about 50 h, when it had the breaks of the substrate. The diamond growth rate measured (0,7 ± 0,1) µm/h is low for economic viability of the process. The spectroscopy of Raman scattering analysis evidences the diamond growth of good quality, approximately in one area of 80 cm 2 , with minimum compressive stress. The properties and the diamond growth rates the surfaces of the used substrate had been uniform. The reached development allows diamond growth 30 µm thickness in 80 cm 2 areas, without breaking of the substrate.