Thermal analysis of submicron nanocrystalline diamond films

Abstract

The thermal properties of sub-μm nanocrystalline diamond films in the range of 0.37–1.1μm grown by hot filament CVD, initiated by bias enhanced nucleation on a nm-thin Si-nucleation layer on various substrates, have been characterized by scanning thermal microscopy. After coalescence, the films have been outgrown with a columnar grain structure. The results indicate that even in the sub-μm range, the average thermal conductivity of these NCD films approaches 400Wm−1K−1. By patterning the films into membranes and step-like mesas, the lateral component and the vertical component of the thermal conductivity, klateral and kvertical, have been isolated showing an anisotropy between vertical conduction along the columns, with kvertical≈1000Wm−1K−1, and a weaker lateral conduction across the columns, with klateral≈300Wm−1K−1.