Structural and Electronic Properties of a Mn Oxide Diffusion Barrier Layer Formed by Chemical Vapor Deposition

A diffusion barrier layer of a few nanometers in thickness is required for a
$\hbox{Cu/}\hbox{SiO}_{2}$
interconnect structure for advanced integrated circuits (ICs). This paper reports a new barrier material and process by chemical vapor deposition (CVD) of a Mn oxide layer using a bis(ethylcyclopentadienyl)manganese precursor. A good adhesion was obtained when the
$\hbox{MnO}_{x}$
layer was deposited below 300
$^{\circ} \hbox{C}$
because of the small amount of carbon inclusion within the layer. The metal–oxide–semiconductor samples of
$\hbox{Cu/}\hbox{MnO}_{x} \hbox{/}\hbox{SiO}_{2}\hbox{/}\hbox{p-Si}$
showed a very low leakage current of less than
$\hbox{10}^{-7}\ \hbox{A/}\hbox{cm}^{2}$
at 4 MV/cm and a negligible shift of the flat-band voltage after thermal annealing and bias temperature annealing. The obtained results indicated that the CVD-deposited
$\hbox{MnO}_{x}$
is an excellent diffusion barrier layer for advanced ICs.