Thermal Stability of Cu/SiOF/Si MOS Capacitor

• Main Authors: Wang Chi-Ning, 王啟寧
• Other Authors: Mao-Chieh Chen
• Format: Others
• Language: en_US
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/83128453027426945892

碩士 === 國立交通大學 === 電子工程系 === 87 === This thesis studies the thermal stability of Cu/SiOF/Si capacitor with and without Ta-nitride (TaN) barrier layer. The SiOF films were deposited by plasma-enhanced chemical vapor deposition (PECVD) with the process gases of tetraethylorthosilicate (TEOS), O2 and CF4. The Ta-nitride films were deposited using reactive sputtering in an Ar/N2 mixed ambient. In the electrical aspect, the breakdown field measurement on the Cu/TaN/SiOF/Si capacitors and capacitance-voltage (C-V) measurement on the Cu/TaN/SiOF/SiO2/Si capacitors were used to characterize the capacity of the barrier in the metallization system. Analysis techniques of SEM and SIMS were used to investigate the degradation mechanism of the capacitors. With a 25nm thick TaN barrier between Cu and SiOF film, the Cu/TaN/SiOF/Si capacitors were able to remain stable at temperatures up to 500℃ from the results of breakdown field measurement. However, the results of the C-V measurement and the SEM micrographs revealed the outgassing of the SiOF film during the thermal process at a temperature of 300℃ led to wreckage of the TaN barrier layer. N2O plasma treatment on the SiOF film improved thermal stability of the Cu/SiOF/Si capacitor up to a temperature of 500℃; moreover, the plasma treatment made the SiOF film immune from outgassing at elevated temperatures, and thus prevented wreckage of the covering TaN layer.