Contacts with interface fermi level tuning layers
Transition metal dichalcogenide (TMD) monolayers are positioned between a contact metal and a semiconductor to pin the Fermi level at the metal-semiconductor interface. The pinned Fermi level can provide for a lower Schottky barrier height between the contact metal and semiconductor than if no TMD were present at the contact metal-semiconductor interface. The height of the Schottky barrier can be tuned through the selection of the transition metal dichalcogenide used for the monolayer. Transition metal dichalcogenides have the chemical formula MX 2 , where M is a transition metal and X=sulfur, selenium, or tellurium. The transition metal dichalcogenides used for metal contact-semiconductor interfaces can have M=titanium, platinum, molybdenum, tungsten, erbium, rhodium, or lanthanum. A lower Schottky barrier height can reduce contact resistance, which can improve transistor performance as the parasitic resistance of source/drain channels approach that of transistor channel as transistor geometries continued to scale.
1 . An apparatus, comprising:
a lower layer comprising silicon;
a first fin extending from a surface of the lower layer, the first fin comprising silicon;
a first layer positioned adjacent to and encompassing the first fin along at least a portion of a length of the first fin, the first layer comprising silicon and an n-type dopant;
a second layer located on at least a portion of a length of the first layer, the length of the first layer extending in a first direction parallel to the surface of the lower layer, the length of the first fin extending in the first direction, the second layer comprising a first metal;
a first monolayer positioned between the first layer and the second layer, the first monolayer comprising a transition metal dichalcogenide (TMD) comprising:
a transition metal; and
sulfur, selenium, or tellurium;
a second fin extending from the surface of the lower layer;
a third layer positioned adjacent to and encompassing the second fin along at least a portion of a length of the second fin, the third layer comprising silicon and a p-type dopant;
a fourth layer located on at least a portion of a length of the third layer, the length of the third layer extending in the first direction, the length of the second fin extending in the first direction, the fourth layer comprising the first metal; and
a second monolayer positioned between the third layer and the fourth layer, the second monolayer comprising the transition metal of the TMD and omitting sulfur, selenium, and tellurium.
2 . The apparatus of claim 1 , wherein the transition metal of the first monolayer is molybdenum, tungsten, platinum, or titanium.
3 . The apparatus of claim 1 , wherein the transition metal of the first monolayer is erbium, lanthanum, or titanium.
4 . The apparatus of claim 1 , wherein the second layer comprises one or more of tungsten, cobalt, titanium, gold, aluminum, molybdenum, chromium, and nickel.
5 . The apparatus of claim 1 , wherein the first layer comprises phosphorous, arsenic, or antimony.
6 . The apparatus of claim 1 , wherein the third layer comprises boron, gallium, or indium.
7 . The apparatus of claim 1 , wherein the first layer further comprises germanium.
8 . The apparatus of claim 1 , the first monolayer is positioned adjacent to one or more outer surfaces of the first layer.
9 . The apparatus of claim 1 , wherein the apparatus is an integrated circuit component.
10 . The apparatus of claim 1 , wherein the apparatus further comprises:
a printed circuit board; and
a first integrated circuit component attached to the printed circuit board, the first integrated circuit component comprising the lower layer, the first fin, the second fin, the first layer, the second layer, the third layer, the fourth layer, the first monolayer, and the second monolayer.
11 . The apparatus of claim 10 , wherein the apparatus further comprises one or more second integrated circuit components attached to the printed circuit board.
12 . The apparatus of claim 1 , wherein the transition metal comprises molybdenum and the second layer comprises molybdenum.
13 . An apparatus, comprising:
a lower layer comprising silicon, the lower layer further comprising a first region including an n-type dopant and a second region including a p-type dopant;
a first layer located above a surface of the lower layer and positioned on the first region of the lower layer, the first region extending from the surface of the lower layer to a depth within the lower layer, the first layer comprising a first metal;
a first monolayer positioned between the first layer and the first region, the first monolayer comprising:
a transition metal; and
sulfur, selenium, or tellurium;
a second layer located above the surface of the lower layer and positioned on the second region of the lower layer, the second layer comprising the first metal; and
a second monolayer positioned between the second layer and the second region, the second monolayer comprising the transition metal without including any one of sulfur, selenium, or tellurium.
14 . The apparatus of claim 13 , wherein the first monolayer comprises a transition metal dichalcogenide.
15 . The apparatus of claim 13 , wherein the transition metal of the first monolayer is molybdenum, tungsten, platinum, or titanium.
16 . The apparatus of claim 13 , wherein the transition metal of the first monolayer is erbium, lanthanum, or titanium.
17 . The apparatus of claim 13 , wherein the first layer comprises one or more of tungsten, cobalt, titanium, gold, aluminum, molybdenum, chromium, and nickel.
18 . The apparatus of claim 13 , wherein the first region comprises phosphorous, arsenic, or antimony.
19 . The apparatus of claim 13 , wherein the second region comprises boron, gallium, or indium.
20 . The apparatus of claim 13 , wherein the first region further comprises germanium.
21 . The apparatus of claim 13 , wherein the apparatus is an integrated circuit component.
22 . The apparatus of claim 13 , wherein the apparatus further comprises:
a printed circuit board; and
a first integrated circuit component attached to the printed circuit board, the first integrated circuit component comprising the lower layer, the first layer, the first monolayer, the second layer, and the second monolayer.
23 . The apparatus of claim 22 , wherein the apparatus further comprises one or more second integrated circuit components attached to the printed circuit board.
24 . The apparatus of claim 13 , wherein the transition metal comprises molybdenum and the second layer comprises molybdenum.