An integrated circuit device includes a substrate, a first transition metal dichalcogenide layer over the substrate, a dielectric layer over the first transition metal dichalcogenide layer, a first gate electrode, and a first source contact and a first drain contact. The first transition metal dichalcogenide layer has a surface roughness greater than 0.5 nm and less than 1 nm. The first gate electrode is over the dielectric layer and a first portion of the first transition metal dichalcogenide layer. The first source contact and the first drain contact are respectively connected with a second portion and a third portion of the first transition metal dichalcogenide layer. The first portion of the first transition metal dichalcogenide layer is between the second and third portions of the first transition metal dichalcogenide layer.

Disclosed are methods of forming PN junction structures, methods of fabricating semiconductor devices using the same, and semiconductor devices fabricated by the same. The method of forming a PN junction structure includes: forming on a substrate a first material layer that includes first transition metal atoms and first chalcogen atoms, loading the first material layer into a process chamber and supplying a gas of second chalcogen atoms, and forming a second material layer by substituting the second chalcogen atoms for the first chalcogen atoms on a selected portion of the first material layer. The first material layer has one of n-type conductivity and p-type conductivity. The second material layer has the other of the n-type conductivity and the p-type conductivity.

Methods for depositing group 5 chalcogenides on a substrate are disclosed. The methods include cyclical deposition techniques, such as atomic layer deposition. The group 5 chalcogenides can be two-dimensional films having desirable electrical properties.

Methods of depositing transition metal dichalcogenide (TMDC) films are described. The TMDC films can be used in electronic devices as, for example, a channel material in both back-end-of-line (BEOL) and front-end-of line (FEOL) applications depending on the TMDC growth temperature.

A semiconductor device includes channel structures spaced apart in a vertical direction; lower/upper first gate insulation patterns contacting lower/upper surfaces of the channel structures; a gate electrode surrounding lower/upper surfaces and a sidewall of the channel structures; and source/drain layers at sides of the gate electrode, wherein the channel structures include first/second 2D material layers stacked in the vertical direction, the first 2D material layer includes a semiconducting TMD including a first transition metal and first chalcogen elements that are bonded at lower/upper sides of the first transition metal, the second 2D material layer includes a second transition metal and a second chalcogen element, the second chalcogen element being bonded at a lower side of the second transition metal, and the second transition metal included in the second 2D material layer is covalently or ionically bonded with an element of the upper first gate insulation pattern.

A method of fabricating a semiconductor device includes forming a semiconductor layer, the semiconductor layer including a two-dimensional semiconductor material, forming a sacrificial layer on the semiconductor layer, forming a metal contact layer on the sacrificial layer, and removing the sacrificial layer. After the sacrificial layer is removed, the semiconductor layer and the metal contact layer are bonded to each other through a van der Waals bond.

A semiconductor device includes a channel on a substrate. The channel includes a 2-dimensional material. A gate insulating layer is on a first portion of the channel. A gate electrode is on a portion of the gate insulating layer. First and second contact patterns are on second portions of the channel, respectively. Each of the first and second contact patterns includes a 2-dimensional material having an intercalation material disposed therein. First and second source/drain electrodes are on the first and second contact patterns, respectively. Each of the first and second source/drain electrodes includes a metal.

A semimetal liner and a metal-insulator-metal (MIM) capacitor (MIMCAP) are described along with the methods of manufacture or fabrication. The MIM capacitor structure includes a liner formed of a thin layer or film of a semimetal, which is a few nanometers thick, e.g., a thickness in the range of about 0.5 nm to about 5 nm or more. The semimetal liner is sandwiched between an electrode layer and a dielectric layer, e.g., a layer of high or ultra-high-k material, thereby providing a cap for the electrode to limit leakage currents in the structure.

A semiconductor device includes a two-dimensional semiconductor layer formed by a two-dimensional semiconductor material having a first formation energy, a two-dimensional metal conductor layer formed by a two-dimensional metal material and covering a surface of the two-dimensional semiconductor layer, and a metal layer covering a surface of the two-dimensional metal conductor layer. The two-dimensional metal material has a second formation energy smaller than the first formation energy. The two-dimensional metal conductor layer is formed by bonding of cations from the metal layer and anions from the two-dimensional semiconductor layer. As such, the contact resistances between the two-dimensional materials and the metals can be effectively reduced, enabling the application of the two-dimensional materials in semiconductor devices such as field-effect transistors.

A memory device includes a transistor and a memory cell. The transistor includes a first gate electrode, a second gate electrode, a channel layer, and a gate dielectric layer. The second gate electrode is over the first gate electrode. The channel layer is located between the first gate electrode and the second gate electrode. The gate dielectric layer is located between the channel layer and the second gate electrode. The memory cell is sandwiched between the first gate electrode and the channel layer.