FINFET WITH BACKGATE, WITHOUT PUNCHTHROUGH, AND WITH REDUCED FIN HEIGHT VARIATION
First Claim
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1. A FinFET comprising:
- a substrate;
a backgate comprising a first layer formed in the substrate, the first layer comprising a first semiconductor;
a second layer formed over the first layer, the second layer comprising a second semiconductor;
a fin channel formed over the second layer, the fin channel comprising a third semiconductor;
a backgate contact through the second layer and in electrical contact with the first layer;
a deep trench isolation region formed down into the substrate; and
wherein the first semiconductor has a first bandgap and the third semiconductor has a third bandgap, wherein the second semiconductor has a second bandgap greater than the first bandgap and the second bandgap.
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Abstract
A FinFET having a backgate and a barrier layer beneath the fin channel of the FinFET, where the barrier layer has a bandgap greater than that of the backgate. The barrier layer serves as an etch stop layer under the fin channel, resulting in reduced fin channel height variation. The backgate provides improved current control. There is less punchthrough due to the higher bandgap barrier layer. The FinFET may also include deeply embedded stressors adjacent to the source/drain diffusions through the high bandgap barrier layer.
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Citations
30 Claims
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1. A FinFET comprising:
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a substrate; a backgate comprising a first layer formed in the substrate, the first layer comprising a first semiconductor; a second layer formed over the first layer, the second layer comprising a second semiconductor; a fin channel formed over the second layer, the fin channel comprising a third semiconductor; a backgate contact through the second layer and in electrical contact with the first layer; a deep trench isolation region formed down into the substrate; and wherein the first semiconductor has a first bandgap and the third semiconductor has a third bandgap, wherein the second semiconductor has a second bandgap greater than the first bandgap and the second bandgap. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method to fabricate a FinFET, the method comprising:
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forming a first semiconductor layer in a substrate; forming a second semiconductor layer over the first semiconductor layer; forming a third semiconductor layer over the second semiconductor layer; etching the third semiconductor layer to form a FinFET fin channel; etching through the second semiconductor layer to the first semiconductor layer and forming an electrical backgate contact to the first semiconductor layer; and forming a deep trench isolation region to the substrate; wherein the first, second, and third semiconductor layers each have, respectively, a first bandgap, a second bandgap, and a third bandgap, wherein the second bandgap is greater than the first bandgap and the second bandgap. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A method to turn ON a FinFET, the FinFET comprising a gate, a backgate, and a substrate, the method comprising:
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coupling the gate of the FinFET to a first rail; and coupling the backgate of the FinFET to a second rail, wherein the backgate comprises a first layer formed in the substrate and comprises a first semiconductor; wherein the gate is formed over a fin channel formed over a second layer, the second layer formed over the first layer and comprising a second semiconductor, the fin channel comprising a third semiconductor; wherein the first semiconductor has a first bandgap and the third semiconductor has a third bandgap, wherein the second semiconductor has a second bandgap greater than the first bandgap and the second bandgap. - View Dependent Claims (29, 30)
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Specification