Fin field effect transistor (FinFET) device structure and method for forming the same
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChang-Yin Chen, Chai-Wei Chang, Bo-Feng Young, Yi-Jen Chen
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Abstract
A FinFET device structure and method for forming the same are provided. The FinFET device structure includes a fin structure formed over a substrate and a gate structure traversing over the fin structure. The gate structure includes a gate electrode layer which includes an upper portion above the fin structure and a lower portion below the fin structure, the virtual surface is formed between the upper portion and the lower portion, and the lower portion has a tapered width which is gradually tapered from the virtual interface to a bottom surface of the lower portion.
Claims20
A method for forming a fin field effect transistor (FinFET) device structure, comprising:
- forming a fin structure over a substrate;
- forming an isolation structure over the substrate, wherein a portion of the fin structure is embedded in the isolation structure;
- and
- forming a gate structure over the fin structure and the isolation structure, wherein the gate structure comprises a gate electrode layer which comprises an upper portion above the fin structure and a lower portion below an upper surface of the fin structure, and the lower portion has a tapered width which is gradually tapered from a virtual interface to a bottom surface of the lower portion, the virtual interface is formed between the upper portion and the lower portion, wherein forming the gate structure comprises:
- forming a dummy gate structure;
- forming an inter-layer dielectric (ILD) structure over the substrate and adjacent to the dummy gate structure;
- removing the dummy gate structure to form a trench in the ILD structure;
- and
- forming a gate dielectric layer and a gate electrode layer in the trench to form the gate structure.
A method for forming a fin field effect transistor (FinFET) device structure, comprising:
- forming a fin structure over a substrate;
- forming an isolation structure over the substrate, wherein the fin structure protrudes above an upper surface of the isolation structure;
- forming a first layer over the fin structure and the isolation structure;
- etching the first layer to form a first gate such that a width of the first gate is narrower adjacent the isolation structure than at an upper surface of the fin structure along a line parallel to a longitudinal axis of the fin structure;
- forming a dielectric layer along opposing sides of the first gate;
- removing the first gate to form a recess in the dielectric layer;
- and
- forming a second gate in the recess.
A method for forming a fin field effect transistor (FinFET) device structure, comprising:
- forming a fin structure over a substrate;
- forming an isolation structure over the substrate, wherein the fin structure protrudes above an upper surface of the isolation structure;
- forming a dummy gate layer over the fin structure and the isolation structure;
- patterning the dummy gate layer to form a dummy gate, wherein the dummy gate has a virtual interface between an upper portion and a lower portion, the lower portion having a tapered width that is gradually tapered from the virtual interface to a bottom surface of the lower portion;
- forming a first spacer along a first sidewall of the dummy gate and a second spacer along a second sidewall of the dummy gate;
- forming a dielectric layer adjacent the first spacer and the second spacer;
- removing the dummy gate;
- and
- forming a gate electrode between the first spacer and the second spacer.
Dependencies are inferred from the claim text.