| 摘要 |
A field effect transistor utilizes an oxide film to obtain satisfactory performance characteristics and ease of manufacture. The field effect transistor includes a gate over a silicon substrate. The gate of the field effect transistor consists of an oxide film on the silicon substrate, a ferroelectric film on the oxide film, and an electrode metal film on the ferroelectric film. The material and the thickness of ferroelectric film are selected such that the product of the relative dielectric constant of ferroelectric film and the electric field across ferroelectric film is less than 15.6 Mv/cm. The ferroelectric film is easily formed on the oxide film. An electric filed across the oxide film of more than 4 MV/cm will result in a break down in the oxide layer. By employing a ferroelectric film with a low relative dielectric constant, the applied electric field across the oxide film is less than 4 Mv/cm. In another embodiment of the invention, a gate includes an oxide layer, an intermediate layer on the oxide layer and a ferroelectric layer on the oxide layer. The intermediate layer provides an improvement to the crystallinity of the ferroelectric layer which results in enhanced performance to the transistor, for example the turn-on voltage. The intermediate layer consists of a titanium layer on a platinum layer. The platinum layer is formed on the oxide layer to prevent the intermediate layer from peeling away from the oxide layer. The titanium layer improves the crystallinity of the ferroelectric layer.
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