Ferroelectric memory devices and operation methods thereof

A semiconductor device, comprising:

• a stack structure of first conductive layers and isolating layers alternating with each other along a first direction;
• and
• a string structure extending in the stack structure along the first direction, the string structure comprising a dielectric layer, a channel layer surrounded by the dielectric layer, a ferroelectric layer surrounded by the channel layer, and a second conductive layer surrounded by the ferroelectric layer,
• wherein the channel layer is between at least one of the first conductive layers and the second conductive layer along a second direction different from the first direction, and the ferroelectric layer is between the channel layer and the second conductive layer along the second direction.

A method, comprising:

• forming a stack structure of first conductive layers and isolating layers alternating with each other along a first direction;
• and
• forming a string structure extending in the stack structure along the first direction, the string structure comprising a dielectric layer, a channel layer surrounded by the dielectric layer, a ferroelectric layer surrounded by the channel layer, and a second conductive layer surrounded by the ferroelectric layer,
• wherein the channel layer is between at least one of the first conductive layers and the second conductive layer along a second direction different from the first direction, and the ferroelectric layer is between the channel layer and the second conductive layer along the second direction.