Effect of Nitridation for High-K Layers by ALCVDTM in Order to Decrease the Trapping in Non Volatile Memories

• Published in: ECS transactions Vol. 11; no. 7; pp. 213 - 225
• Main Authors: Grampeix, Helen, Colonna, Jean-Philippe, Molas, Gabriel, Bocquet, Marc, Martin, François, Rochat, Névine, Martinez, Eugénie, Licitra, Christophe, Veyron, Thomas, Papon, Anne-Marie, Gely, Marc, Yckache, Karim
• Format: Journal Article
• Language: English
• Published: 28.09.2007
• ISSN: 1938-5862; 1938-6737
• DOI: 10.1149/1.2779085

In non-volatile memories, high-k materials such as Al2O3, HfO2, and hafnium aluminates are good candidates as interpoly layers. In order to decrease the parasitic trapping of the interpoly stack, the effect of post deposition nitridation (PDN) on different high-κ films was investigated. Several characterizations were performed on those films such as Angle Resolved X-ray Photo-electron Spectroscopy (AR-XPS), Auger Electron Spectroscopy (AES), Attenuated Total Reflection - Fourier Transform Infrared spectroscopy (ATR-FTIR) and Vacuum UltraViolet Spectroscopy Ellipsometry (VUV-SE). A correlation between the nitrogen incorporation and the crystallization was demonstrated. Al-rich films remain amorphous after PDN, with an incorporation of nitrogen in the film volume. Meanwhile, Hf-rich films crystallized after PDN, with nitrogen incorporated only at the high-κ / Si substrate interface. Also nitrogen increases the crystallization temperature onset, which leads to a reduction of charge trapping after high temperature spike anneals. Nitrided amorphous hafnium aluminate films are good candidates as interpoly layer.