One Transistor Ferroelectric Memory Devices with Improved Retention Characteristics

• Published in: Japanese Journal of Applied Physics 2002-11, Vol.41 (Part 1, No. 11B), p.6890-6894
• Main Authors: Li, Tingkai, Hsu, Sheng Teng, Ulrich, Bruce, Stecker, Lisa, Evans, Dave
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.41.6890

Authors fabricated Pb5Ge3O11 (PGO) MFMPOS (M: metal, F: ferroelectrics, P: polysilicon, O: oxide, S: Si) memory transistor devices using MOCVD selective deposition, damascene structure and chemical mechanical planarization (CMP) processes. These processes have no need to etch the ferroelectric material. Etching-induced damages are avoided. The one-transistor memory devices show memory windows around 2-3 V. The memory windows are almost saturated from operation voltage of 3 V. For the one transistor memory device, after writing the off state (-5 V), the drain current (ID) at a VD of 0.1 V and a VG of 0, 0.5, and 1 V is about 2 x 10-14 A. After writing the on state (+5 V), the drain current (ID) at a VD of 0.1 V and a VG of 0, 0.5, and 1 V is about 1 x 10-5 A. The ratio of the on state current to the off state current is close to 9 order. The 1 T devices show very good memory characteristics. The one-transistor memory devices also show very good retention properties. 14 refs.