In this work, high-performance TiN metal nanocrystal nonvolatile memories using a p+ poly-Si gate and a Al2 O3 blocking dielectric layer with trigate structure are fabricated on silicon-on-insulator substrate. Devices with moderate transistor performance and superior memory properties are demonstrated. A memory window as high as 5 V is achieved after Program/Ease (P/E) operation at ±10 V for 0.1 s, with only 18 and 33% charge loss at room temperature and at 85°C after 10 years storage. Only +0.5 V window shift and almost no window narrowing after 105 P/E operations can be obtained. Furthermore, a device with larger nanocrystals has better P/E characteristics and superior retention performance.