Deposition of thick cubic boron nitride thin films by dual ion beam deposition

In this work we report on the production of cubic boron nitride (c-BN) thin films by Dual Ion Beam Deposition (DIBD). The interest of this work is to search for an ion-beam-assisted deposition (IBAD) method able to produce thick (> 1 um) low-stress c-BN thin films and, hence, with potential industrial application. This is not applicable in the case of IBAD using electron beam evaporation, since the material contained in the liner limits the maximum process time and, in addition, the fact that boron sublimes, makes difficult a fine control over the evaporation rate. Our DIBD system is equipped with two commercial Kauffman-type ion guns. Boron atoms were sputtered by direct Ar+ bombardment of a 3” boron target. The ions impinge under an angle of 45° and are produced with a 3 cm beam-diameter ion gun. The growth process was assisted by concurrent bombardment from a mixture of argon and nitrogen ions extracted from a 5 cm beam-diameter ion gun. For the cubic phase growth, the substrate temperature and ion assisting parameters were chosen in order to reach the required momentum transfer per incoming atom [1]. The stress release was achieved by additional ion bombardment with medium-energy N2+ ions (35 keV) during the growth process [2].

REFERENCES:

[1] D.J. Kester, R. Messier, J. Appl. Phys. 72 (1992) 504.
[2] C. Fitz, A. Kolitsch, W. Möller, Appl. Phy. Lett. 80 (2001) 55.