Title:
FERROELECTRIC MEMORY ELEMENT AND METHOD OF PRODUCING THE SAME
Document Type and Number:
WIPO Patent Application WO/1998/053506
Kind Code:
A1
Abstract:
A ferroelectric film having a low permittivity and used for a ferroelectric memory element, and a ferroelectric film having a high melting point and used for a ferroelectric memory element. A FET (20) is constituted of a gate oxide film (24), a floating gate (26), a ferroelectric film (28) and a control gate (30) laminated in this order on a channel-forming region (CH) formed in a silicon semiconductor substrate (22). The ferroelectric film (28) is constituted of a thin film of a mixed crystal Sr�2?(Ta�1-x?Nb�x?)�2?O�7?. Both Sr�2?Nb�2?O�7? and Sr�2?Ta�2?O�7? have a tetragonal crystalline structure and have nearly the same lattice constant. They have low specific inductivities and high melting points. However, Sr�2?Nb�2?O�7? has too high a Curie temperature that is related to the ferroelectric property and Sr�2?Ta�2?O�7? has too low a Curie temperature. Therefore, a mixed crystal Sr�2?(Ta�1-x?Nb�x?)�2?O�7? thereof is prepared to obtain a ferroelectric film (28) having a desired Curie Temperature.
Inventors:
NAKAMURA TAKASHI (JP)
FUJIMORI YOSHIKAZU (JP)
FUJIMORI YOSHIKAZU (JP)
Application Number:
PCT/JP1998/002207
Publication Date:
November 26, 1998
Filing Date:
May 18, 1998
Export Citation:
Assignee:
ROHM CO LTD (JP)
NAKAMURA TAKASHI (JP)
FUJIMORI YOSHIKAZU (JP)
NAKAMURA TAKASHI (JP)
FUJIMORI YOSHIKAZU (JP)
International Classes:
H01B3/12; H01L21/8246; H01L21/8247; H01L27/10; H01L27/105; H01L29/78; H01L29/788; H01L29/792; (IPC1-7): H01L29/788; H01L21/8247
Foreign References:
| JPH09213899A | 1997-08-15 |
Other References:
PREPRINTS OF THE JOINT CONGRESS OF APPLIED PHYSICS, XX, XX, no. 02, 1 January 1996 (1996-01-01), XX, pages 409, XP002917247
NAKAMURA T., ET AL.: "STUDY OF FERROELECTRIC THIN FILMS FOR APPLICATION TO NDRO NONVOLATILE MEMORIES.", IEICE TECHNICAL REPORT, DENSHI JOUHOU TSUUSHIN GAKKAI, JP, vol. 93., no. 350., 1 January 1993 (1993-01-01), JP, pages 53 - 59., XP002917248, ISSN: 0913-5685
See also references of EP 0940856A4
NAKAMURA T., ET AL.: "STUDY OF FERROELECTRIC THIN FILMS FOR APPLICATION TO NDRO NONVOLATILE MEMORIES.", IEICE TECHNICAL REPORT, DENSHI JOUHOU TSUUSHIN GAKKAI, JP, vol. 93., no. 350., 1 January 1993 (1993-01-01), JP, pages 53 - 59., XP002917248, ISSN: 0913-5685
See also references of EP 0940856A4
Attorney, Agent or Firm:
Furutani, Hideo (23-20 Esaka-cho 1-chom, Suita-City Osaka, JP)
Download PDF:
Previous Patent: LATERAL MOS TRANSISTOR DEVICE
Next Patent: FEEDBACK CONTROL SYSTEM FOR ULTRASOUND PROBE
Next Patent: FEEDBACK CONTROL SYSTEM FOR ULTRASOUND PROBE