Cobalt Salicided Ultra Shallow Junction Formation Technologies for ULSI Applications

• Main Authors: Kuo Wei Chu, 朱國偉
• Other Authors: Wen Luh Yang
• Format: Others
• Language: en_US
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/68191083942091798468

碩士 === 逢甲大學 === 電機工程學系 === 87 === Several methods for forming cobalt salicided p+/n ultra shallow junction have been studied. The application for p+/n shallow junction formed with low energy ion implantation was first investigated in the thesis. The shallower doping profiles were obtained by the lower energy BF2+ ion implantation (3KeV~10KeV). Furthermore, We found that capping a TEOS layer could improve the periphery leakage for junction leakage. In this thesis, A p+/n ultra shallow junction with junction depth about 43.4nm, low reverse leakage current density (~7.93nA/cm2 at-5V), low periphery leakage (~0.08nA/cm at -5V) and a good forward ideality factor, n (~1.01) by 3KeV BF2+ ion implantation was achieved. The Co-polycided p+/n ultra shallow junctions formed by using the implanted polysilicon as a solid diffusion source with different activated ambiance were investigated. Results show that the p+/n ultra shallow junction depth depends on the activation ambiance is first reported so far. We found that nitridation is not only increase the junction leakage but also enhance the boron diffusion (NED effect), caused by NO bond from the spectra of the FTIR analysis. On the contrary, activation in N2O ambiance has contributed to improve thermal stability of Co-polycided films. The implantation of Ar+ into Co-salicide was also applied to investigate the improvement of thermal stability. Results shows that the better thermal stability of CoSi2 films can be obtained than those of no-Ar+-implantation samples. But Ar+ implantation will lead a higher junction leakage and deeper junction depth from I-V and SIMS measurement.