| AVS 58th Annual International Symposium and Exhibition | |
| Electronic Materials and Processing Division | Thursday Sessions |
| Session EM-ThP |
| Session: | Electronic Materials and Processing Poster Session |
| Presenter: | Juliana Miyoshi, State University of Campinas, Brazil |
| Authors: | J. Miyoshi, State University of Campinas, Brazil A.R. Silva, State University of Campinas, Brazil F.A. Cavarsan, State University of Campinas, Brazil J.A. Diniz, State University of Campinas, Brazil L.P.B. Lima, State University of Campinas, Brazil |
| Correspondent: | Click to Email |
Titanium-Aluminum Oxide (TiAlO) and Titanium-Aluminum Oxynitride (TiAlON) high k films have received considerable attention due to their electrical and physical properties, which are from the composition of Titanium Oxide and Aluminum Oxide properties, such as higher permittivity (k~80) and higher band gap (Eg~8.8 eV), respectively, than others high k (such as HfO2 and ZrO2) films [1,2]. Furthermore, this composition can reduce the undesirable effects on sub-32 nm MOS devices, which are high leakage current, due to the value of band offset of 2.8 eV to Al2O3, and EOT higher than 2 nm, due to relatively low k between 8 and 10, respectively. In this work, Titanium-Aluminum Oxide (TiAlO) and Titanium-Aluminum Oxynitride (TiAlON) were obtained on Si wafers as follow: 0.75 nm Titanium (Ti) and 0.25 nm Aluminum (Al) were sequentially deposited by vacuum e-beam evaporation, without any substrate heating. The evaporation pressure was 3x10-8 Torr, and the Ti and Al evaporation rates were of 0.1 nm/min, resulting in Al/Ti/Si structures. ECR (electron cyclotron resonance) plasma oxidation and oxynitridation process were carried out on these strucures using O2/Ar and O2/N2/Ar gases, respectively, to get the TiAlO and TiAlON films on Si. Physical thickness values between 6.3 and 6.9 nm were determined by ellipsometry. XPS (X-Ray Photoelectron Spectroscopy) analysis was performed and the formation of TiAlO and TiAlON films was confirmed. These films were used as gate insulators in MOS capacitors fabricated with TiN (20nm)/Al (180 nm) electrodes, and they were used to obtain capacitance–voltage (C–V) measurements. A relative dielectric constant of 3.9 was adopted to extract the equivalent oxide thickness (EOT) of films from C–V curves under strong accumulation condition, resulting in values between 0.5 and 1.4 nm, and effective charge densities of about 1011 cm-2. Because of these results, nMOSFETs with TiN/Al gate electrode and TAON gate dielectric were fabricated and characterized by current–voltage (I–V) curves. These results indicate that the obtained TiAlON and TiAlO films are suitable gate insulator for the next generation (MOS) devices.
Reference:
[1] Miyoshi J., Diniz J.A., Barros A.D., Doi I., Von Zuben A.A.G., (2010) Microelectronic Engineering, 87 (3), pp. 267-270.
[2] A. P. Alekhin, A. A. Chouprik, S. A. Gudkova, and A. M. Markeev, Yu. Yu. Lebedinskii, Yu. A. Matveyev, and A. V. Zenkevich, 01A302-1 J. Vac. Sci. Technol. B 29(1), Jan/Feb 2011.