Title :
The process window of a-Si/Ti bilayer metallization for an oxidation-resistant and self-aligned TiSi2 process
Author :
Lou, Yung-Song ; Win, C.-Y. ; Cheng, Huang-Chung
Author_Institution :
Adv. Semicond. Device Res. Lab., Nat. Chiao-Tung Univ., Hsin-Chu, Taiwan
fDate :
8/1/1992 12:00:00 AM
Abstract :
The dependences of both oxidation-resistant and self-aligned silicidation properties on the thicknesses of top amorphous-Si (a-Si) and Ti metal in an a-Si/Ti bilayer process are presented. It is shown that a thin silicide layer formed during the reaction between a-Si and Ti films becomes a stable oxidation and nitridation barrier for oxygen- and nitrogen-related impurities. Moreover, the formation sequence of the silicide phase depends not only on the annealing temperature but also on the thickness of the Ti film. In addition, the preferential orientation of the silicide phase after annealing at high temperature also shows a strong dependence on the thickness of Ti film, which is attributed to the difference of the grain size in the polycrystalline silicide film. The allowed process window for the a-Si thickness can be determined experimentally and a reproducible and homogeneous self-aligned TiSi2 film can be easily obtained by using the a-Si/Ti bilayer process in salicide applications despite high-level contaminations of oxygen impurities in both the as-deposited Ti film and the annealing ambient
Keywords :
Auger effect; X-ray diffraction examination of materials; amorphous semiconductors; annealing; chemical interdiffusion; elemental semiconductors; metallisation; oxidation; scanning electron microscope examination of materials; silicon; titanium; AES depth profile; SEM; Si-Ti bilayer metallisation; X-ray diffraction; annealing ambient; annealing temperature; grain size; homogeneous self-aligned film; nitridation barrier; oxidation barrier; polycrystalline silicide film; process window; salicide applications; self aligned TiSi2 process; semiconductor; Annealing; Contamination; Etching; Grain size; Impurities; MOS devices; Metallization; Silicidation; Silicides; Temperature dependence;
Journal_Title :
Electron Devices, IEEE Transactions on
