FinFET with isolation
First Claim
Patent Images
1. A method for forming a device comprising:
- providing a substrate prepared with a device region;
forming a fin in the device region, the fin includes top and bottom fin portions, wherein the top fin portion serves as a body of a fin type transistor;
forming an isolation layer on the substrate, wherein the isolation layer has a top isolation surface disposed below the top fin portion;
forming at least one isolation buffer in the bottom fin portion, leaving the top fin portion crystalline, wherein the at least one isolation buffer does not extend throughout the entire length of the bottom fin portion and partially isolates the top fin portion from the substrate, wherein forming the at least one isolation buffer comprisesperforming an oxidation process to form at least one oxidized portion in the bottom fin portion,removing the at least one oxidized portion to form a complete void, andfilling the complete void with an oxide material having a plurality of voids, wherein the at least one isolation buffer is a hybrid isolation buffer;
forming source/drain (S/D) regions in the top portions of the fin; and
forming a gate wrapping around the fin, wherein the gate comprises a top gate portion on top of the fin and side gate portions extending from a top surface of the fin towards the top isolation surface, wherein the side gate portions extend below the S/D regions and are in direct contact with sidewalls of the bottom fin portion.
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Abstract
Devices and methods for forming a device are presented. The method includes providing a substrate prepared with a device region. A fin is formed in the device region. The fin includes top and bottom portions. An isolation layer is formed on the substrate. The isolation layer has a top isolation surface disposed below a top fin surface, leaving an upper fin portion exposed. At least one isolation buffer is formed in the bottom fin portion, leaving the top fin portion crystalline, the top fin portion serves as a body of a fin type transistor. Source/drain (S/D) regions are formed in the top portions of the fin and a gate wrapping around the fin is provided.
29 Citations
19 Claims
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1. A method for forming a device comprising:
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providing a substrate prepared with a device region; forming a fin in the device region, the fin includes top and bottom fin portions, wherein the top fin portion serves as a body of a fin type transistor; forming an isolation layer on the substrate, wherein the isolation layer has a top isolation surface disposed below the top fin portion; forming at least one isolation buffer in the bottom fin portion, leaving the top fin portion crystalline, wherein the at least one isolation buffer does not extend throughout the entire length of the bottom fin portion and partially isolates the top fin portion from the substrate, wherein forming the at least one isolation buffer comprises performing an oxidation process to form at least one oxidized portion in the bottom fin portion, removing the at least one oxidized portion to form a complete void, and filling the complete void with an oxide material having a plurality of voids, wherein the at least one isolation buffer is a hybrid isolation buffer; forming source/drain (S/D) regions in the top portions of the fin; and forming a gate wrapping around the fin, wherein the gate comprises a top gate portion on top of the fin and side gate portions extending from a top surface of the fin towards the top isolation surface, wherein the side gate portions extend below the S/D regions and are in direct contact with sidewalls of the bottom fin portion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for forming a device comprising:
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providing a substrate prepared with a device region; forming a fin structure in the device region, the fin structure includes top and bottom fin portions, wherein the top fin portion serves as a body of a fin type transistor; forming an isolation layer on the substrate, wherein the isolation layer has a top isolation surface disposed below the top fin portion; forming at least one isolation segment in the bottom fin portion and leaving the top fin portion crystalline, wherein forming the at least one isolation segment comprises performing an oxidation process to form at least one oxidized portion in the bottom fin portion, removing the at least one oxidized portion to form a complete void, and filling the complete void with an oxide material having a plurality of voids, wherein the at least one isolation segment is a hybrid isolation segment, the at least one isolation segment partially isolates the top fin portion from the substrate; forming first and second source/drain (S/D) regions of the fin type transistor, wherein each of the S/D regions include a base S/D portion disposed within the top fin portion and a raised S/D portion disposed on the base S/D portion; and forming a gate wrapping around the fin structure, wherein the gate comprises a top gate portion on top of the fin and side gate portions extending from a top surface of the fin towards the top isolation surface, wherein the side gate portions extend below the S/D regions and in direct contact with sidewalls of the bottom fin portion. - View Dependent Claims (16, 17, 18)
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19. A method for forming a device comprising:
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providing a substrate prepared with a device region; forming a fin in the device region, the fin includes top and bottom portions; forming a dummy gate over the substrate; forming an isolation layer on the substrate, wherein the isolation layer has a top isolation surface disposed below the top fin portion, wherein forming the isolation layer comprises providing an isolation layer having an initial thickness T1 and performing an etch to recess the isolation layer from the initial thickness T1 to a final thickness T2; forming protective liners on sidewalls of an upper fin portion over the isolation layer prior to recessing the isolation layer from T1 to T2, wherein forming the protective liners include a blanket deposition process to form a protective layer on the fin and isolation layer, and performing an etch to remove horizontal portions of the protective layer, leaving vertical portions of the protective layer to form the protective liners; forming at least one isolation buffer in the bottom fin portion, leaving the top fin portion crystalline, wherein the at least one isolation buffer does not extend throughout the entire length of the bottom fin portion and partially isolates the top fin portion from the substrate, the top fin portion serves as a body of a fin type transistor, wherein forming the at least one isolation buffer comprises forming first and second isolation buffers which are separated from each other under the S/D regions, wherein forming the first and second isolation buffers comprises recessing the isolation layer from T1 to T2 after forming the protective liners, doping exposed portions of the fin in-between the protective liners and a top surface of the recessed isolation layer, and performing an oxidation process to the exposed doped fin portions to form first and second oxide portions, wherein the dummy gate protects the bottom fin portion under a channel region below the gate from being oxidized; performing an etch to remove the first and second oxide portions to form first and second complete voids below the S/D regions; filling the complete voids with an oxide material having a plurality of voids to form the first and second isolation buffers, wherein the isolation buffers are hybrid isolation buffers; forming source/drain (S/D) regions in the top portions of the fin; and forming a gate wrapping around the fin, wherein the gate comprises a top gate portion on top of the fin and side gate portions extending from a top surface of the fin towards the top isolation surface, wherein the side gate portions extend below the S/D regions and in direct contact with sidewalls of the bottom fin portion.
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Specification