Effect of sputtering target power on preferred orientation in nc-TiN/a-SiN_x nanocomposite thin films

Nanocrystalline TiN (or nc-TiN) has been imbedded in amorphous silicon nitride (a-SiN_x) matrix to form a nanocomposite thin film (nc-TiN/a-SiN_x) via magnetron sputtering deposition on silicon wafer. Two important effects of the Si₃N₄ sputtering target power on the formation of nc-TiN/a-SiN_x have been studied: (1) Aside from forming a-SiN_x in the matrix, Si atoms also imbed into TiN to form (Ti,Si)N solid solution crystallites. At low target power, the solid solution is substitutional. With increase of power, the amount of silicon "dissolved" in the TiN crystallite increases, and in the meantime, the interstitial components increase which is manifested in the increase in the TiN lattice parameter. (2) The crystallites have a preferred orientation varying with the deposition target power. As conveniently described by the coefficient of texture, the degree of preferred orientation along direction decreases and finally tails off with increase of power. At the same time, the crystallites orient along and direction and eventually direction dominants.