Improved stability of electrical properties of nitrogen-added Al2O3 films grown by PEALD as gate dielectric

• We fabricated Al2O3 films by PEALD and compared them with those by RPALD.
• Electrical properties of Al2O3 films with and without post-annealing were compared.
• The breakdown field was enhanced for introducing nitrogen gas in Al2O3 films.
• In the PEALD process, we confirmed the self-limiting mechanism.

The electrical properties of Al2O3 films have been studied as the dielectric materials for electronic devices which require a low leakage current and high breakdown field. In this work, Al2O3 films with various thicknesses (as low as 10–30 nm) were deposited onto Si substrates by plasma-enhanced atomic layer deposition (PEALD), and current density– field curves were measured after post-annealing to verify their electrical properties. One thing to note is that, during PEALD, nitrogen gas was introduced to improve the thermal stability of the Al2O3 films. Breakdown field for add-nitrogen Al2O3 of 30 nm-thick film was enhanced from 6 MV/cm to 10 MV/cm as incorporating nitrogen.

Figure optionsDownload as PowerPoint slide