Growth and characterization of Al2O3 gate dielectric films by low-pressure metalorganic chemical vapor deposition

• Published in: Microelectronic engineering 2003-04, Vol.66 (1-4), p.842-848
• Main Authors: SHAO, Qi-Yue, LI, Ai-Dong, LING, Hui-Qin, DI WU, YUAN WANG, YAN FENG, YANG, Sen-Zu, LIU, Zhi-Guo, MU WANG, MING, Nai-Ben
• Format: Article
• Language: English
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/s0167-9317(02)01009-2

Ultrathin Al2O3 films have been deposited on n-Si substrates by low-pressure metalorganic chemical vapor deposition (MOCVD) as gate dielectrics for next generation MOSFET applications. Al(acac)3 was used as metalorganic precursor. Impacts of substrate temperature and post-annealing in O2 or N2 on equivalent oxide thickness (EOT), leakage current density (JA) and carbon residue of Al2O3 films have been studied. It is found that post-annealing is necessary for ultrathin Al2O3 films to obtain good electrical properties. The EOT shows slight deposition temperature dependence and the lowest EOT value with #~ 0.8 nm is obtained at 600DGC. Typical Al2O3 ultrathin films have larger frequency dependence and EOT of #~ 1.2 nm with JA of 36 mA/cm2 at Vg= + 1 V. AES depth profiles demonstrate that post-annealing in an O2 atmosphere could effectively eliminate the carbon contamination of Al2O3 films. Meanwhile, further post-annealing in N2 could decrease the JA of Al2O3 films to 8 mA/cm2.