Ferroelectric memory device and method of forming the same

A method comprising:

• forming a word line over a substrate;
• forming a ferroelectric layer over the word line;
• forming a channel region over the ferroelectric layer;
• and
• forming a bit line and a source line on opposite sidewalls of the channel region, wherein forming the bit line and the source line comprises:
• depositing a first oxide semiconductor layer on the ferroelectric layer and on the opposite sidewalls of the channel region;
• etching the first oxide semiconductor layer, wherein portions of the first oxide semiconductor layer remain on the opposite sidewalls of the channel region after the etching;
• depositing a second oxide semiconductor layer over the ferroelectric layer and the remaining portions of the first oxide semiconductor layer;
• and
• depositing a conductive material over the second oxide semiconductor layer.

A method comprising:

• forming a memory layer over a substrate;
• forming a channel region on the memory layer;
• and
• forming a first source/drain structure and a second source/drain structure on the memory layer, wherein forming the first source/drain structure and the second source drain structure each comprise:
• forming a first source/drain layer on the memory layer, wherein the
• channel region extends on the memory layer from the first source/drain layer of the first source/drain structure to the first source/drain layer of the second source/drain structure;
• forming a second source/drain layer on the first source/drain layer, wherein the second source/drain layer is different from the first source/drain layer;
• and
• forming a metal layer on the second source/drain layer
• wherein at least one of the first source/drain layer or second source/drain layer is an oxide semiconductor material.