Dual Work Function Recessed Access Device and Methods of Forming
AssigneeMicron Technology, Inc.
InventorsVenkatesan Anathan, Sanh D. Tang
Life of this patent
Estimating the term…
Abstract
A recessed access device having a gate electrode formed of two or more gate materials having different work functions may reduce the gate-induced drain leakage current losses from the recessed access device. The gate electrode may include a first gate material having a high work function disposed in a bottom portion of the recessed access device and a second gate material having a lower work function disposed over the first gate material and in an upper portion of the recessed access device.
Claims22
1-25. (canceled)
A recessed access device, comprising:
- semiconductor material having at least one trench therein;
- a gate dielectric over a surface of the at least one trench;
- a first gate material lining over only a lowest-most portion of the at least one trench;
- and
- a second gate material within the at least one trench over the first gate material lining, the second gate material being of different composition from composition of the first gate material, the second gate material projecting outwardly within the at least one trench relative to the first gate material lining that is over only said lowest-most portion of the at least one trench.
The recessed access device of claim 25, further comprising a third gate material within the at least one trench and over the second gate material, the third gate material being of different composition from composition of the first gate material and of different composition from composition of the second gate material.
A recessed access device, comprising:
- semiconductor material having an elevationally outermost surface and having at least one trench therein;
- a gate dielectric over a surface of the at least one trench;
- a first gate material over at least a portion of the gate dielectric in a bottom portion of the at least one trench and having an elevationally outermost surface within the at least one trench that is elevationally inward of the elevationally outermost surface of the semiconductor material;
- a second gate material over the first gate material in at least a portion of the at least one trench, the second gate material being of different composition from composition of the first gate material;
- and
- a third gate material in at least a portion of the at least one trench over the first gate material and the second gate material, the third gate material contacting the at least a portion of the gate dielectric in the at least one trench, the third gate material being of different composition from composition of the first gate material and of different composition from composition of the second gate material.
A recessed access device, comprising:
- semiconductor material having an elevationally outermost surface and having at least one trench therein;
- a gate dielectric over a surface of the at least one trench;
- a first gate material within the at least one trench over at least a portion of the gate dielectric in a bottom portion of the at least one trench, the first gate material being formed to be half circle-shaped in a cross section transverse the at least one trench and having a planar elevationally outermost surface within the at least one trench in the cross section that is elevationally inward of the elevationally outermost surface of the semiconductor material, all of the first gate material being received entirely within the at least one trench;
- and
- a second gate material overlying at least a portion of the first gate material, the second gate material being of different composition from composition of the first gate material.
A recessed access device, comprising:
- semiconductor material having at least one trench therein;
- a gate dielectric over a surface of the at least one trench, the gate dielectric comprising an arcuate outer surface in a bottom portion of the at least one trench;
- a first gate material over at least a portion of the gate dielectric in the bottom portion of the at least one trench, the first gate material comprising an arcuate outer surface in a bottom portion of the at least one trench;
- and
- a second gate material over the arcuate outer surface of the first gate material in at least a portion of the at least one trench, the second gate material being of different composition from composition of the first gate material, the second gate material having an upper neck portion within the at least one trench and a lower shouldered portion within the at least one trench in a cross section transverse the at least one trench, the upper neck portion being laterally centered relative to the shouldered portion, the upper neck portion in including a portion within the at least one trench that projects elevationally outward of all first gate material that is within the at least one trench.
Dependencies are inferred from the claim text.