Develop High-K Nanocrystal Materials and Devices

The project is to apply those new materials as Ti and Ta with RF sputtering to fabricate noble Ti and Ta nanocrystals. The formation of the Ti and Ta nanocrystal quantum dots are found by rapid thermal annealing when the heating temperature is over than the melting point. By the way, different high-k materials (GdTi、HfTi) and metal materials (Ta、Sm) in our study are also used to form the nanocrystal quantum dots. For the tunneling and control oxide materials, we use different isolation materials (Al2O3、HfO2、Gd2O3 and TiO2) to replace conventional SiO2, and that can improve electron tunneling the tunneling oxide more easily to increase the paogram and erase speed, and to prevent the charge loss for data retention and endurance. Besides, the N2O plasma is used to improve defect traps, breakdown electric field, and surface morphology for the nanocrystals. Finally, we combine the above developed nanocrystals to fabricate new SONOS multi-layer memory devices. The programming and erasing speeds of the nanocrystal devices are studied under different operation voltages and times, and the charge loss situation is also investigated for process improvements. Finally, the endurance cycling test is used to observe the memory window variation of the nanocrystal devices through many programming/erasing operations for a long time. It’s expectedthat the developed nanocrystal devices can be applied practically in the nonvolatile memory.

Project ID:PB9807-2072
External Project ID:NSC98-2221-E182-017