A heating and diffusion barrier based on TaSiNx for miniaturized IC devices

Highly resistive TaSiNx films investigated as candidates for heating and diffusion-barrier layers for miniaturized IC devices such as a sensor or a phases-change random access memory (PCRAM). The obtained resistivity, between 0.069–1.21 Ω cm, increases with increasing nitrogen content up to 52.83%, and fulfills the requirements as a suitable heating layer. All the as-deposited films were amorphous, and the films with substantial nitrogen content showed excellent thermal stability The amorphous structure had a very smooth surface which was stable at temperatures up to 800 °C. In addition to its heating capability, the amorphous structure with no grain boundaries was found to also act as a good diffusion barrier effect in contact with a tungsten electrode as determined by AES an TEM analysis. The barrier effect was evaluated by an annealing at 500 and 600 °C in Ar atmosphere for 30 min, respectively. The highly resistive TaSiNx heating layer successfully obstructed the diffusion of tungsten atoms from the W electrodes even when the layer was only 10 nm thick. With increasing N content, the heating and diffusion-barrier layer for PCRAM was proposed as a typical example of many potential applications.