Raman Spectroscopy Investigation of Cubic Boron Nitride Single Crystals and Layers on Si(100)

T. Werninghaus, M. Friedrich, D.R.T. Zahn
Technische Universität Chemnitz, Institut für Physik
Halbleiterphysik
D-09107 Chemnitz
Germany

J. Hahn, F. Richter
Technische Universität Chemnitz, Institut für Physik
Technische Physik / Physik fester Körper
D-09107 Chemnitz
Germany

Micro-Raman Spectroscopy (µ-RS) measurements were performed on cubic boron nitride (c-BN) single crystals and c-BN thin films deposited on Si(100) by magnetron sputtering of a h-BN target. The 482.5nm laser line of a Kr+ laser as well as the 488.0nm laser line of an Ar+ laser were found to be most sensitive to the detection of c-BN. For single crystals of different sizes (<100nm, 1µm, 100µm, 1mm) and the nanocrystalline c-BN layers on Si(100) substrates the crystal size influence on the frequency position and the lineshape of the longitudinal (LO) and transversal optical (TO) phonon features was investigated. With decreasing crystal size a shift towards lower frequencies as well as a broadening and increasing asymmetry of the LO and TO phonon is observed. A comparison of these results with a phonon-confinement model is discussed. For the c-BN layers on Si(100) substrates additional two-dimensional Raman mappings of the Si signal were performed revealing the influence of the transparent hard coating on the substrate.