Transistors having stacked 2D material channel layers and heterogeneous 2D material contacts layers epitaxial to the 2D material channel layers

An apparatus, comprising:

• a plurality of semiconductor channel layers interleaved with a plurality of gate layers, each of the gate layers comprising a gate electrode layer and a gate dielectric layer, wherein the semiconductor channel layers comprise a first transition metal dichalcogenide comprising a first transition metal of tungsten or molybdenum and a first chalcogen of sulfur or selenium;
• first contact layers and second contact layers on opposite lateral ends of and epitaxial to of the semiconductor channel layers, wherein the first and second contact layers comprise a second transition metal dichalcogenide comprising a second transition metal of tungsten or molybdenum and a second chalcogen of tellurium;
• a gate contact coupled to the gate electrode layers;
• and
• a source contact coupled to the first contact layers and a drain contact coupled to the second contact layers, wherein one of the first contact layers comprises a first portion on a first semiconductor channel layer of the semiconductor channel layers and within a first recess between first and second gate dielectric layers on opposite sides of the first semiconductor channel layer, another one of the first contact layers comprises a second portion on a second semiconductor channel layer of the semiconductor channel layers and within a second recess between third and fourth gate dielectric layers on opposite sides of the second semiconductor channel layer, and the first portion and the second portion are separated by and are in contact with a third portion of the source contact that separates the first portion and the second portion.

An apparatus, comprising:

• a plurality of semiconductor channel layers interleaved with a plurality of gate layers, each of the plurality of gate layers comprising a gate electrode layer and a gate dielectric layer, wherein the semiconductor channel layers comprise a first 2D material, the first 2D material comprising a first compound of a first metal and a first chalcogen and having a first crystalline phase;
• first contact layers and second contact layers on opposite lateral ends of and epitaxial to of the semiconductor channel layers, wherein the first and second contact layers comprise a second 2D material, the second 2D material comprising a second compound of a second metal and a second chalcogen and having a second crystalline phase, wherein at least one of the second metal, the second chalcogen, or the second crystalline phase is different with respect to the first metal, the first chalcogen, or the first crystalline phase, respectively;
• a gate contact coupled to the gate electrode layers;
• and
• a source contact coupled to the first contact layers and a drain contact coupled to the second contact layers, wherein one of the first contact layers comprises a first portion on a first semiconductor channel layer of the semiconductor channel layers and within a first recess between first and second gate dielectric layers on opposite sides of the first semiconductor channel layer, another one of the first contact layers comprises a second portion on a second semiconductor channel layer of the semiconductor channel layers and within a second recess between third and fourth gate dielectric layers on opposite sides of the second semiconductor channel layer, and the first portion and the second portion are separated by and are in contact with a third portion of the source contact that separates the first portion and the second portion.