As discussed above, the memory array 200 may also include an oxide semiconductor (OS) layer 92. The OS layer 92 may provide channel regions for the TFTs 204 of the memory cells 202. For example, when an appropriate voltage (e.g., higher than a respective threshold voltage (Vth) of a corresponding TFT 204) is applied through a corresponding conductive line 72, a region of the OS layer 92 that intersects the conductive line 72 may allow current to flow from the conductive lines 106 to the conductive lines 108 (e.g., in the direction indicated by arrow 205).
A memory film 90 is disposed between the conductive lines 72 and the OS layer 92, and the memory film 90 may provide gate dielectrics for the TFTs 204. In some embodiments, the memory film 90 comprises a ferroelectric material, such as a hafnium oxide, hafnium zirconium oxide, silicon-doped hafnium oxide, or the like. Accordingly, the memory array 200 may also be referred to as a ferroelectric random access memory (FERAM) array. Alternatively, the memory film 90 may be a multilayer structure comprising a layer of SiNx between two SiOx layers (e.g., an ONO structure), a different ferroelectric material, a different type of memory layer (e.g., capable of storing a bit), or the like.