THE ASSESSMENT OF SOME COBALT AND COBALT-TELLURIUM COMPLEXES FOR MOCVD APPLICATIONS

Eleven cobalt complexes of the types [Co(CO)(2)(NO)L](L = PEt(3), TeMe (2) or TeEt(2)) and [(eta(3)-C(3)H(3)R(2))Co(CO)(2)L] (R = H or Me; L = CO, PEt(3), TeEt(2) or CNR' with R' = Pr-i, Bu(t) or Cy; Cy is cyclo hexyl) have been prepared and assessed for MOCVD applications. Measure ment of vapour pressures by the Knudson effusion method has establishe d that the room-temperature volatilities of [Co(CO)(2)(NO) (TeMe(2))], and the allyl complexes [(eta(3)-C3H5)Co(CO)(3)], (4)Me)Co(CO)(3)],[( eta(3)-C(3)H(3)Me(2))Co(CO)(3)] and [(eta(3)-C3H5)Co(CO)(2)(CNBu(t))] are sufficient (0.1-4.0 mmHg) to achieve high concentrations in the va pour state. Vapour-phase thermal degradation at 180-250 degrees C of s even complexes carried in a stream of hydrogen gave metal deposits, wh ich were analysed by EDX or XPS. The best behaved complexes were [Co(C O)(2)(NO)(TeMe(2))] and [(eta(3)-C3H5)Co(CO)(3)], which gave clean Co films after decomposition at 150 and 250 degrees C, respectively.