Semiconductor device having source/drain contacts connecting 2-D material layer and method for forming the same

A method, comprising:

• forming a 2-D material layer over a substrate, wherein a monolayer of the 2-D material layer comprises transition metal atoms and chalcogen atoms;
• forming a gate structure over the 2-D material layer;
• removing portions of the chalcogen atoms from the 2-D material layer to reveal portions of the transition metal atoms of the 2-D material layer;
• and
• forming source/drain contacts over the 2-D material layer, wherein metal atoms of the source/drain contacts form metallic bonds with the portions of the transition metal atoms of the 2-D material layer.

A device, comprising:

• a substrate;
• and
• a first transistor over the substrate, comprising:
• a first 2-D material channel layer, wherein the first 2-D material channel layer is made of a transition metal dichalcogenide (TMD);
• a first gate structure wrapping around the first 2-D material channel layer;
• and
• first source/drain contacts in contact with opposite ends of the first 2-D material channel layer, wherein metal atoms of the first source/drain contacts and transition metal atoms of the first 2-D material channel layer are free of chalcogen atoms interposed therebetween.