Atomic layer deposition of CMOS gates with variable work functions
View Patent ↗Structures, systems and methods for transistors having gates with variable work functions formed by atomic layer deposition are provided. One transistor embodiment includes a first source/drain region, a second source/drain region, and a channel region therebetween. A gate is separated from the channel region by a gate insulator. The gate includes a ternary metallic conductor formed by atomic layer deposition.
1. A method for forming a transistor pair, comprising:
forming a PMOS transistor;
forming an NMOS transistor; and
wherein forming the NMOS and the PMOS transistors includes forming a varied gate composition having a varied work function on each respective transistor in order to control a threshold voltage for each respective transistor to a same magnitude;
wherein forming a varied gate composition includes:
forming a gate with a binary metallic conductor for one of the NMOS and PMOS transistors; and
forming a gate with a ternary metallic conductor for the other one of the NMOS and PMOS transistors.
2. The method of claim 1 , wherein forming a binary metallic conductor includes forming tantalum nitride (TaN).
3. The method of claim 1 , wherein forming a binary metallic conductor includes forming titanium nitride (TiN).
4. The method of claim 1 , wherein forming a binary metallic conductor includes forming tungsten nitride (WN).
5. The method of claim 1 , wherein forming a ternary metallic conductor includes forming Tantalum Aluminum Nitride (TaAlN).
6. The method of claim 1 , wherein forming a ternary metallic conductor includes forming Titanium Aluminum Nitride (TiAlN).
7. The method of claim 1 , wherein forming a ternary metallic conductor includes forming Titanium Silicon Nitride (TiSiN).
8. The method of claim 1 , wherein forming a ternary metallic conductor includes forming Tungsten Aluminum Nitride (WAlN).
9. The method of claim 1 , further includes forming a refractory metal on the ternary metallic conductor.
10. A method for forming a transistor pair, comprising:
forming a PMOS transistor;
forming an NMOS transistor; and
wherein forming the NMOS and the PMOS transistors includes forming a varied gate composition having a varied work function on each respective transistor in order to control a threshold voltage for each respective transistor to a same magnitude,
wherein forming a varied gate composition includes forming a ternary metallic conductor using atomic layer deposition, and depositing a refractory metal on the gate.
11. The method of claim 10 , wherein:
forming a ternary metallic conductor includes forming Tungsten Aluminum Nitride (WAlN); and
depositing a refractory metal includes depositing Tungsten (W).
12. The method of claim 10 , wherein:
forming a ternary metallic conductor includes forming Tantalum Aluminum Nitride (TaAlN); and
depositing a refractory metal includes depositing Tantalum (Ta).
13. The method of claim 10 , wherein:
forming a ternary metallic conductor includes forming Titanium Aluminum Nitride (TiAlN); and
depositing a refractory metal includes depositing Titanium (Ti).
14. The method of claim 10 , wherein:
forming a ternary metallic conductor includes forming Titanium Silicon Nitride (TiSiN); and
depositing a refractory metal includes depositing Titanium (Ti).