Surface chemistry of precursors for film growth: pentakisdimethylamido tantalum

The behavior of the tantalum-bearing precursor, pentakisdimethylamido tantalum-Ta(N(CH3)(2))(5), PKDMATa-has been studied on Ni foil and on thin films derived From PKDMATa.. In temperature-programmed desorption following adsorption on Ni at 100 K, molecular PKDMATa appears with a peak at 265 K, H-2, with two peaks between 250 and 500 K, and N-2 with a peak at 768 K. For multilayers, there are also small desorption peaks between 170 and 160 K tentatively assigned as (CH3)(2)NM(CH3)(2). Ta, N, and C remain after heating to 900 K. C-H bonds begin dissociating below 250 K, C-N and Ta-N bonds are broken by 550 K and C begins diffusing into Ni above 550 E;. With the substrates held st elevated temperatures, reaction products that evolve during dosing include H-2, N-2, CH4, and C2H4. The film composition, TaNxCy, is strongly temperature-dependent. (C) 1999 Elsevier Science B.V. All rights reserved.