AVS 46th International Symposium
    Electronic Materials and Processing Division Thursday Sessions
       Session EM2-ThA

Paper EM2-ThA7
Bi@sub 4@Ti@sub 3@O@sub 12@ Ferroelectric Thin Films Deposited on Silicon by Pulse Injection Metal-Organic Chemical Vapor Deposition

Thursday, October 28, 1999, 4:00 pm, Room 611

Session: Silicon Carbide and Dielectrics on Si
Presenter: S.K. Lee, Seoul National University, Korea
Authors: S.K. Lee, Seoul National University, Korea
H.J. Kim, Seoul National University, Korea
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Bi@sub 4@Ti@sub 3@O@sub 12@ is one of the well-known bismuth-based layered perovskite materials. This compound has attracted much attention because of its characteristic anisotropic property. Especially, the low coercive field along c-axis, about 3.5 kV/cm, has made Bi@sub 4@Ti@sub 3@O@sub 12@ thin film a very promising gate dielectric for a ferroelectric field effect memory device. For this application, ferroelectric thin film has to be fabricated at low temperature in order to keep the abrupt interface with the semiconductor substrate and the composition of the film has to be uniform. By these requirements, metal-organic chemical vapor deposition (MOCVD) was taken as the fabrication method of Bi@sub 4@Ti@sub 3@O@sub 12@ thin film on p-type (100) silicon substrate. Solid Bi(C@sub 6@H@sub 5@)@sub 3@ and liquid Ti(OC@sub 3@H@sub 7@)@sub 4@ were chosen as precursors of bismuth and titanium, respectively, because of their good stability and complete decomposition ability. However, the great difference in formation kinetics of TiO@sub 2@ and Bi@sub 2@O@sub 3@ made it very difficult to control the Bi@sub 4@Ti@sub 3@O@sub 12@ /Si interface and the film composition. In order to overcome this problem, pulse injection method was introduced, in which input precursors were varied periodically during deposition for compensating the lower reactivity of Bi(C@sub 6@H@sub 5@)@sub 3@ with oxygen. By this pulse injection method, abrupt Bi@sub 4@Ti@sub 3@O@sub 12@ /Si interface was attained and the composition of Bi@sub 4@Ti@sub 3@O@sub 12@ thin film was also very uniform. The properties of Bi@sub 4@Ti@sub 3@O@sub 12@ thin films were strongly dependent on the substrate temperature and pulse injection conditions.