Ferroelectric field effect transistor and preparation method thereof

Abstract

The invention discloses a ferroelectric field effect transistor and a preparation method thereof. The method comprises the following steps: firstly executing a front-end process: preparing a basic field effect transistor on a substrate through employing a front gate process, and forming a source region, a drain region, and a dielectric gate located between the source region and the drain region; and executing a back-end process: forming first insulating layers and a first metal interconnection structure located between the first insulating layers on the basic field effect transistor, forming a ferroelectric gate on the first insulating layer, and electrically connecting the ferroelectric gate to the dielectric gate through the first metal interconnection structure. The ferroelectric gate is prepared through the back-end process, and the transistor part prepared through the front-end process can still adopt the front gate process with lower cost and higher yield, so that the problems caused by the back gate process are avoided, and the problem that the ferroelectric material is incompatible with the temperature of the front-end process in the integration process is also solved. In addition, the area of the ferroelectric gate located on the insulating layers is flexible and adjustable, matching of a ferroelectric capacitor and a transistor dielectric capacitor can be achieved by adjusting the area of the ferroelectric gate, and therefore a larger storage window is obtained.

Description

technical field [0001] The invention belongs to the technical field of microelectronic devices, and more specifically relates to a ferroelectric field effect transistor and a preparation method thereof. Background technique [0002] A ferroelectric field effect transistor (FeFET) can be obtained by inserting a ferroelectric gate into the gate of an ordinary field effect transistor (MOSFET). The surface of the ferroelectric transistor channel can be changed by changing the remanent polarization direction of the ferroelectric gate by applying a gate voltage. Potential to obtain threshold switching window, so as to realize information storage. As a new type of nonvolatile memory, ferroelectric transistor has the advantages of low power consumption, high speed and non-destructive readout, and is considered to be a new type of memory with great application potential. At the same time, due to the polycrystalline and multi-domain characteristics of the ferroelectric gate, differen...

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Problems solved by technology

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a ferroelectric field effect transistor and its preparation method, the purpose of which is to solve the conflict between the crystallization temperature of the ferroelectric material and the ion implantation activation temperature, the ferroelectric capacitance and the gate dielectric Capacitance matching and technical problems of ferroelectric materials and gate dielectric interface defects

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