Apparatus and circuits with dual threshold voltage transistors and methods of fabricating the same
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorChan-Hong Chern
Life of this patent
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Abstract
Apparatus and circuits with dual threshold voltage transistors and methods of fabricating the same are disclosed. In one example, a semiconductor structure is disclosed. The semiconductor structure includes: a substrate; a first layer comprising a first III-V semiconductor material formed over the substrate; a first transistor formed over the first layer, and a second transistor formed over the first layer. The first transistor comprises a first gate structure comprising a first material, a first source region and a first drain region. The second transistor comprises a second gate structure comprising a second material, a second source region and a second drain region. The first material is different from the second material.
Claims20
A semiconductor structure, comprising:
- a substrate;
- a first layer comprising a first III-V semiconductor material formed over the substrate;
- a polarization modulation layer disposed above the first layer;
- a passivation layer disposed at least partially on the polarization modulation layer;
- a first transistor formed over the substrate, wherein the first transistor comprises a first gate structure comprising a first material, a first source region and a first drain region;
- and
- a second transistor formed next to the first transistor over the substrate, wherein the second transistor comprises a second gate structure comprising a second material, a second source region and a second drain region, wherein:
- the first gate structure is disposed partially on the polarization modulation layer and partially on the passivation layer;
- the second gate structure is disposed partially on the polarization modulation layer and partially on the passivation layer;
- and
- the first material has a different work function than that of the second material.
A circuit, comprising:
- a first transistor including a first gate, a first source and a first drain;
- and
- a second transistor including a second gate, a second source and a second drain, wherein:
- the first transistor and the second transistor are formed next to each other on a same semiconductor wafer comprising a substrate,
- a first layer comprising a first III-V semiconductor material is disposed over the substrate,
- a polarization modulation layer is disposed above the first layer,
- a passivation layer is disposed at least partially on the polarization modulation layer,
- the first gate is disposed partially on the polarization modulation layer and partially on the passivation layer,
- the second gate is disposed partially on the polarization modulation layer and partially on the passivation layer, and
- the second gate comprises a material that has a different work function than a material of the first gate.
A method for forming a semiconductor structure, comprising:
- forming a first layer comprising a first III-V semiconductor material over a substrate;
- forming a polarization modulation layer above the first layer;
- forming a passivation layer at least partially on the polarization modulation layer;
- forming a first transistor over the substrate, wherein the first transistor comprises a first gate structure comprising a first material, a first source region and a first drain region;
- and
- forming a second transistor next to the first transistor over the substrate, wherein the second transistor comprises a second gate structure comprising a second material, a second source region and a second drain region, wherein the first transistor and the second transistor are both high electron mobility transistors, wherein:
- the first gate structure is formed partially on the polarization modulation layer and partially on the passivation layer;
- the second gate structure is formed partially on the polarization modulation layer and partially on the passivation layer;
- and
- the first material has a different work function than that of the second material.
Dependencies are inferred from the claim text.