Impact of TaN/Ta copper barrier on full PEALD TiN/Ta2O5/TiN 3D damascene MIM capacitor performance

Abstract

MIM capacitors are widely integrated for RF and analog applications. A high density full PEALD TiN/Ta2O5/TiN capacitor is integrated among copper interconnect following an innovative 3D damascene architecture. The impact of a TaN/Ta layer, introduced to avoid Cu diffusion, on both TiN electrode properties and integrated MIM stack performance is studied. Unexpected lower current was obtained without the barrier layer. As a result, up to 17 fF/mum2 capacitance densities were achieved with breakdown voltage over 15 V and excellent voltage linearity.