Method for producing a tensioned layer on a substrate, and a layer structure
AssigneeForschungszentrum Julich GmbH
InventorSiegfried Mantl
Life of this patent
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Abstract
The invention relates to a method for producing a tensioned layer on a substrate involving the following steps: producing a defect area in a layer adjacent to the layer to be tensioned, and; relaxing at least one layer adjacent to the layer to be tensioned. Additional layers can be epitaxially deposited. Layer structures formed in this manner are advantageously suited for components of all types.
Claims96
A method of producing a strained layer (9) on a substrate (1, 2) with the steps:
- producing a defect region (7) in a layer (2, 4, 5, 11) neighboring a layer (3) to which strain is to be imparted,
- relaxing at least one layer (4, 11) neighboring the layer (3) to which strain is to be imparted.
The method according to one of the preceding claims characterized in that the layer structure, for relaxation, is subjected to a thermal treatment and/or oxidation.
A method according to one of the preceding claims characterized in that at least one first layer (4;
- 11) is deposited upon the layer (3) to be strained.
The method according to one of the preceding claims characterized in that the first layer (4, 11) has a different degree of stress than the layer (3) to be strained.
The method according to one of the preceding claims characterized in that the defect region (7) is produced in the first layer (4;
- 11).
The method according to one of the preceding claims in which a further relaxing layer is disposed between the substrate (1, 2) and the layer (3) to be strained.
The method according to one of the preceding claims characterized in that the defect region (7) is produced in the substrate.
The method according to one of the preceding claims characterized in that the defect region (7) is produced in the layer (3) to be strained itself.
The method according to one of the preceding claims characterized in that two neighboring layers (11, 13) of the layer (12) to be strained have other degrees of dislocation than the layer (12) to be strained.
The method according to one of the preceding claims in which a plurality of layers (11, 13) are relaxed.
The method according to one of the preceding claims in which a plurality of layers (3, 12) to be strained, have strain imparted to them.
The method according to one of the preceding claims characterized in that on the first layer (4, 11) epitactically at least one further layer (5;
- 12, 13) with respectively a different lattice structure is deposited.
The method according to one of the preceding claims characterized in that the defect region (7) is produced in the second layer (5;
- 13).
The method according to one of the preceding claims characterized in that on the layer to which strain is to be imparted (3) at least one graded layer is deposited as the first layer (4).
The method according to one of the preceding claims characterized in that at the region of the layer (3) to be strained, the graded layer (4) has a degree of dislocation which is different from that of the layer (3) to be strained.
The method according to one of the preceding claims characterized in that a defect region (7) is produced in a graded layer (4).
The method according to one of the preceding claims in which an epitactic layer structure comprising a plurality of layers is produced on a substrate (1, 2, 3, 4, 5, 11, 12, 13) in a deposition process.
The method according to one of the preceding claims in which the first layer (4, 11) is relaxed by a thermal treatment.
The method according to one of the preceding claims characterized in that for the thermal treatment a temperature between 550 degrees and 1200 degrees C. is selected.
The method according to one of the preceding claims characterized in that for the thermal treatment, a temperature between 700 degrees and 980 degrees C. is selected.
A method according to one of the preceding claims characterized in that the thermal treatment is carried out in an inert atmosphere.
The method according to one of the preceding claims characterized in that the thermal treatment is carried out in a reducing or oxidizing or nitriding atmosphere and especially in nitrogen.
The method according to one of the preceding claims characterized in that the relaxation is carried out over a limited region of a layer.
The method according to one of the preceding claims in which a mask (6) is applied.
The method according to one of the preceding claims characterized in that the defect region (7) is produced by ion implantation.
The method according to the preceding claim characterized in that for the implantation, hydrogen ions or helium ions are selected.
The method according to one of the preceding claims characterized in that the hydrogen ions or helium ions are implanted with a dose of 3×1015 to 4×1016 cm−2, especially with a dose of 0.5×1016 to 2.5×1016 cm−2.
The method according to one of the preceding claims characterized in that for the implantation, Si ions are selected.
The method according to the preceding claim characterized in that Si ions are implanted with a dose of about 0.5×1014 to 5×1014 cm−2.
The method according to one of the preceding claims characterized in that for the implantation, carbon ions, nitrogen ions, fluorine ions, boron ions, phosphorous ions, arsenic ions, germanium ions, antimony ions, sulfur ions, neon ions, argon ions, krypton ions and/or xenon ions are selected.
The method according to one of the preceding claims characterized in that at least two implantations are carried out.
The method according to one of the preceding claims characterized in that a hydrogen implantation is carried out in combination with a helium implantation.
The method according to one of the preceding claims characterized in that a boron implantation is carried out in combination with a hydrogen implantation.
The method according to one of the preceding claims, characterized in that two implantations are carried out to produce two defect regions in the first layer (4) and in the second layer (5).
The method according to one of the preceding claims characterized in that the wafer during the ion implantation is tilted at an angle greater than 7 degrees, especially at an angle of 30 to 60 degrees.
The method according to one of the preceding claims characterized in that between two implantations a thermal treatment is carried out.
The method according to one of the preceding claims characterized in that the defect region (7) is produced by a change in the temperature during the formation of one of the layers (4, 5;
- 11).
The method according to one of the preceding claims characterized in that the defects are produced in a Si—C layer by thermal treatment.
The method according to one of the preceding claims characterized in that as the substrate, an amorphous layer, especially of an insulator (2) is selected.
The method according to one of the preceding claims characterized in that an SOI substrate (1, 2, 3) is chosen as the base structure for the substrate.
The method according to the preceding claim characterized in that the silicon surface layer (3) of the SOI substrate (1, 2, 3) is the layer (3) to be strained and the SiO2 of the SOI substrate (1, 2, 3) forms the insulator (2) on the substrate (1).
The method according to one of the preceding claims characterized in that an SIMOX or BESOI substrate is selected as the base structure for the substrate.
The method according to one of the preceding claims characterized by selecting a silicon on sapphire as the base structure for a substrate.
The method according to one of the preceding claims characterized by selecting a substrate that becomes viscous at a temperature required for the relaxation.
The method according to one of the preceding claims characterized in that SiO2, glass, SiC, Si—Ge, graphite, diamond, quartz glass, GdGa-garnet, III-V semiconductor and III-V nitride are selected as the material for the substrate (1, 2).
The method according to one of the preceding claims in which an insulator (2) on a substrate (1) is selected.
The method according to one of the preceding claims characterized by the selection of Si—Ge or Si—Ge—C or Si—C as the material for the first layer which is disposed on the layer (3) to be strained.
The method according to one of the preceding claims characterized by the selection of silicon as the material for the layer (3) to be strained.
The method according to one of the preceding claims characterized by the choice of silicon as the material for the second layer (5) which is disposed upon the first layer (4).
The method according to one of the preceding claims characterized by the selection of Si—Ge as the material for a graded layer.
The method according to the preceding claim characterized in that the germanium concentration in the graded layer decreases from the interface with the layer (3) to be strained to the surface of the graded layer.
The method according to one of the preceding claims characterized in that the germanium concentration in a Si—Ge layer at the interface with the layer (3) to be strained is 100 percent.
The method according to one of the preceding claims characterized in that the total layer thickness of the layer structure is so selected that during the growth of the applied layers (4;
- 11, 13) these do not produce any noticeable relaxation.
The method according to one of the preceding claims characterized in that the dislocation density after the growth amounts to less than 105 cm−2.
The method according to one of the preceding claims, characterized in that a layer (3) to be strained with a thickness d3 in the range of 1 to 50 nanometers is selected.
The method according to one of the preceding claims, characterized in that a layer (3) to be strained with a thickness d3 in the range of 5 to 30 nanometers is selected.
The method according to one of the preceding claims, characterized in that a first layer (4) with a thickness d4 close to the critical layer thickness is selected.
The method according to one of the preceding claims, characterized by the selection of a layer thickness ratio d4/d3 of greater than about 10.
The method according to one of the preceding claims, characterized in that a second layer (5) with a thickness d5=50-1000 nanometer is selected.
The method according to one of the preceding claims, characterized in that a second layer (5) with a thickness d5=300-500 nanometer is selected.
The method according to one of the preceding claims in which the layer (3) to be strained is locally strained.
The method according to one of the preceding claims characterized in that the layer (3) to be strained is locally strained in the regions which are vertical in a plane with the defect region.
The method according to one of the preceding claims characterized in that the defect region (7) is produced at a spacing of 500 nanometers from the layer to be relaxed.
The method according to one of the preceding claims characterized in that the defect region (7) is arranged at a spacing of 50 to 100 nanometers above the layer (4) arranged upon the layer (3) to be strained.
The method according to one of the preceding claims characterized in that the first and second layers (4, 5;
- 11, 12, 13) after producing the strained layer (9) or after producing a strained region, are removed.
The method according to one of the preceding claims in which etching, especially wet chemical material-selective etching, is used.
The method according to one of the preceding claims in which etched trenches (15) are produced in the depth of the layers (2, 3, 4, 5, 9, 11, 12, 13).
The method according to one of the preceding claims characterized in that after producing the etched trenches (15) a relaxation of the layer (4;
- 11) or a further layer, especially by a thermal treatment, is carried out.
The method according to one of the preceding claims characterized in that the trenches (15) are filled with insulating material to produce shallow trench insulation (14).
The method according to one of the preceding claims characterized in that at least one further thermal treatment is carried out for relaxation of one or more layers.
The method according to one of the preceding claims characterized in that a strained layer (9) and/or an unstrained layer (3) are produced with a surface roughness of less than 1 nanometer.
The method according to one of the preceding claims characterized in that a surface roughness of layers (3, 9) is further reduced by the growth of a thermal oxide thereon.
The method according to one of the preceding claims characterized in that on a strained region of the layer (9) and n- and/or p-MOSFET is produced.
The method according to one of the preceding claims characterized in that a further epitactic layer (10) comprising silicon or silicon/germanium (Si—Ge) or an Si—Ge—C layer or a germanium layer are deposited.
The method according to one of the preceding claims characterized in that on a strained silicon-germanium (Si—Ge) region (11) p-MOSFETs are produced as further epitactic layers or as nonrelaxed layers structures.
The method according to one of the preceding claims characterized in that on unstrained region (3) of the layer 3 to be strained, bipolar transistors are processed.
The method according to one of the preceding claims characterized in that for producing a bipolar transistor, a silicon-germanium layer is applied.
A layer structure comprising a layer (9, 3) on a substrate (1, 2), characterized in that the layer (9, 3) is partly strained.
The layer structure according to the preceding claim characterized in that the strained region (9) of the layer (9, 3) lies in a plane and is coplanar with and adjacent the unstrained region (3) of the layer (9, 3).
Dependencies are inferred from the claim text.