Inverted field-effect device with polycrystalline silicon/germanium channel
First Claim
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1. An integrated circuit, comprising:
- a first field-effect transistor, havingsource and drain diffusions of a first conductivity type located in and defining a channel region therebetween in a monocrystalline semiconductor body, and a gate electrode, formed in a first thin-film layer of polycrystalline semiconducting material, which is capacitively coupled to said channel region through a first gate dielectric layer;
a second field-effect transistor, having source and drain diffusions of a second conductivity type located in and defining a channel region therebetween in a second thin-film layer of polycrystalline semiconducting material, and a gate electrode, formed in said monocrystalline body, which is capacitively coupled to said channel region through a second gate dielectric layer;
wherein said first and second gate dielectric layers have different thicknesses at all locations.
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Abstract
A CMOS device architecture which includes substrate-gated inverted PMOS transistors, as well as bulk NMOS. The inverted-PMOS channels are formed in a different layer from the NMOS gates, and these layers may even have different compositions. Moreover, the NMOS and inverted-PMOS devices have different gate oxide layers, so the thicknesses can be independently optimized. The drain underlap of the inverted device is defined by a patterning step, so it can be increased for high-voltage operation if desired.
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Citations
22 Claims
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1. An integrated circuit, comprising:
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a first field-effect transistor, having source and drain diffusions of a first conductivity type located in and defining a channel region therebetween in a monocrystalline semiconductor body, and a gate electrode, formed in a first thin-film layer of polycrystalline semiconducting material, which is capacitively coupled to said channel region through a first gate dielectric layer; a second field-effect transistor, having source and drain diffusions of a second conductivity type located in and defining a channel region therebetween in a second thin-film layer of polycrystalline semiconducting material, and a gate electrode, formed in said monocrystalline body, which is capacitively coupled to said channel region through a second gate dielectric layer; wherein said first and second gate dielectric layers have different thicknesses at all locations. - View Dependent Claims (2, 5, 8)
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3. An integrated circuit, comprising:
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a first field-effect transistor, having source and drain diffusions of a first conductivity type located in and defining a channel region therebetween in a monocrystalline semiconductor body, and a gate electrode, formed in a first thin-film layer of polycrystalline semiconducting material, which is capacitively coupled to said channel region through a first gate dielectric layer; a second field-effect transistor, having source and drain diffusions of a second conductivity type located in and defining a channel region therebetween in a second thin-film layer of polycrystalline semiconducting material, and a gate electrode, formed in said monocrystalline body, which is capacitively coupled to said channel region through a second gate dielectric layer; wherein said first and second gate dielectric layers have different thicknesses; and wherein said second polycrystalline film, but not said first polycrystalline film, has a total thickness which is less than 1000 Å
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4. An integrated circuit, comprising:
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a first field-effect transistor, having source and drain diffusions of a first conductivity type located in and defining a channel region therebetween in a monocrystalline semiconductor body, and a gate electrode, formed in a first thin-film layer of polycrystalline semiconducting material, which is capacitively coupled to said channel region through a first gate dielectric layer; a second field-effect transistor, having source and drain diffusions of a second conductivity type located in and defining a channel region therebetween in a second thin-film layer of polycrystalline semiconducting material, and a gate electrode, formed in said monocrystalline body, which is capacitively coupled to said channel region through a second gate dielectric layer; wherein said first and second gate dielectric layers have different thicknesses; and wherein said second polycrystalline film has a total thickness which is less than two-thirds that of said first polycrystalline film.
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6. An integrated circuit, comprising:
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a first field-effect transistor, having source and drain diffusions of a first conductivity type located in and defining a channel region therebetween in a monocrystalline semiconductor body, and a gate electrode, formed in a first thin-film layer of polycrystalline semiconducting material, which is capacitively coupled to said channel region through a first gate dielectric layer; a second field-effect transistor, having source and drain diffusions of a second conductivity type located in and defining a channel region therebetween in a second thin-film layer of polycrystalline semiconducting material, and a gate electrode, formed in said monocrystalline body, which is capacitively coupled to said channel region through a second gate dielectric layer; where in said first and second gate dielectric layers have different thicknesses; and wherein said first and second polycrystalline films have different thicknesses.
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7. An integrated circuit, comprising:
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a first field-effect transistor, having source and drain diffusions of a first conductivity type located in and defining a channel region therebetween in a monocrystalline semiconductor body, and a gate electrode, formed in a first thin-film layer of polycrystalline semiconducting material, which is capacitively coupled to said channel region through a first gate dielectric layer; a second field-effect transistor, having source and drain diffusions of a second conductivity type located in and defining a channel region therebetween in a second thin-film layer of polycrystalline semiconducting material, and a gate electrode, formed in said monocrystalline body, which is capacitively coupled to said channel region through a second gate dielectric layer; wherein said first and second gate dielectric layers have different thicknesses; and wherein said first and second field-effect transistors are interconnected to provide a CMOS logic gate.
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9. An integrated circuit, comprising:
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a first field-effect transistor, having source and drain diffusions of a first conductivity type located in and defining a channel region therebetween in a monocrystalline semiconductor body, and a gate electrode, formed in a first thin-film layer of polycrystalline semiconducting material, which is capacitively coupled to said channel region through a first gate dielectric layer; a second field-effect transistor, having source and drain diffusions of a second conductivity type located in and defining a channel region therebetween in a second thin-film layer of polycrystalline semiconducting material, and a gate electrode, formed in said monocrystalline body, which is capacitively coupled to said channel region through a second gate dielectric layer, wherein said first and second gate dielectrics have different effective thicknesses; wherein said drain region of said second transistor does not overlie said gate thereof, and said source and drain are asymmetrically located with respect to said gate.
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10. An integrated circuit, comprising:
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a first field-effect transistor, having source and drain diffusions of a first conductivity type located in and defining a channel region therebetween in a monocrystalline semiconductor body, and a gate electrode, formed in a first thin-film layer of polycrystalline semiconducting material, which is capacitively coupled to said channel region through a first gate dielectric layer; a second field-effect transistor, having source and drain diffusions of a second conductivity type located in and defining a channel region therebetween in a second thin-film layer of polycrystalline semiconducting material, and a gate electrode, formed in said monocrystalline body, which is capacitively coupled to said channel region through a second gate dielectric layer, wherein said second polycrystalline film, but not said first polycrystalline film, has a total thickness which is less than 1000 Å
;wherein said drain region of said second transistor does not overlie said gate thereof, and said source and drain are asymmetrically located with respect to said gate.
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11. An integrated circuit, comprising:
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a first field-effect transistor, having source and drain diffusions of a first conductivity type located in and defining a channel region therebetween in a monocrystalline semiconductor body, and a gate electrode, formed in a first thin-film layer of polycrystalline semiconducting material, which is capacitively coupled to said channel region through a first gate dielectric layer; a second field-effect transistor, having source and drain diffusions of a second conductivity type located in and defining a channel region therebetween in a second thin-film layer of polycrystalline semiconducting material, and a gate electrode, formed in said monocrystalline body, which is capacitively coupled to said channel region through a second gate dielectric layer, wherein said second polycrystalline film has a total thickness which is less than two-thirds that of said first polycrystalline film; wherein said drain region of said second transistor does not overlie said gate thereof, and said source and drain are asymmetrically located with respect to said gate.
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12. An integrated circuit, comprising:
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a first field-effect transistor, having source and drain diffusions of a first conductivity type located in and defining a channel region therebetween in a monocrystalline semiconductor body; and
a gate electrode, formed in a first thin-film layer of polycrystalline semiconducting material, which is capacitively coupled to said channel region through a first gate dielectric layer;a second field-effect transistor, having source and drain diffusions of a second conductivity type located in and defining a channel region therebetween in a second thin-film layer of polycrystalline semiconducting material, and a gate electrode, formed in said monocrystalline body, which is capacitively coupled to said channel region through a second gate dielectric layer, wherein said first and second polycrystalline films have different thicknesses; wherein said drain region of said second transistor does not overlie said gate thereof, and said source and drain are asymmetrically located with respect to said gate.
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13. An integrated circuit, comprising:
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a first field-effect transistor, having source and drain diffusions of a first conductivity type located in and defining a channel region therebetween in a monocrystalline semiconductor body near a first surface thereof, and a gate electrode, formed in a first thin-film layer of polycrystalline semiconducting material, which is capacitively coupled to said channel region through a first gate dielectric layer; a second field-effect transistor, having source and drain diffusions of a second conductivity type located in and defining a channel region therebetween in a second thin-film layer of polycrystalline semiconducting material, and a gate electrode, formed in said monocrystalline body, which is capacitively coupled to said channel region through a second gate dielectric layer; and a third field-effect transistor, having source diffusions of said first conductivity type located near said first surface of said monocrystalline body, and a gate positioned to control current flow from said source into said monocrystalline body away from said first surface thereof; and a fourth transistor, having source and drain diffusions of said second conductivity type located in said monocrystalline body; said second and third transistors being connected to define a high-voltage driver stage, and said first and fourth transistors being connected to define a low-voltage inverter which is operatively connected to drive said gate terminals of said second and third transistors. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification