Semiconductor structure having strained semiconductor and method therefor
View Patent ↗A first semiconductor structure has a silicon substrate, a first silicon germanium layer grown on the silicon, a second silicon germanium layer on the first silicon germanium layer, and a strained silicon layer on the second silicon germanium layer. A second semiconductor structure has a silicon substrate and an insulating top layer. The silicon layer of the first semiconductor structure is bonded to the insulator layer to form a third semiconductor structure. The second silicon germanium layer is cut to separate most of the first semiconductor structure from the third semiconductor structure. The silicon germanium layer is removed to expose the strained silicon layer where transistors are subsequently formed, which is then the only layer remaining from the first semiconductor structure. The transistors are oriented along the <100> direction and at a 45 degree angle to the <100> direction of the base silicon layer of the second silicon.
1. A method for forming a semiconductor device comprising:
forming an insulating layer on a surface of a first semiconductor substrate;
forming a first semiconductor layer comprising silicon and germanium over a second semiconductor substrate;
forming a strained semiconductor layer comprising silicon over the first semiconductor layer;
adhering the first semiconductor layer to the insulating layer;
cleaving through the first semiconductor layer;
removing any remaining portion of the semiconductor layer; and
forming a transistor on the strained semiconductor layer, wherein the transistor is aligned along a <100> direction of the strained semiconductor layer.
2. The method of claim 1 , wherein the strained semiconductor layer is in a tensile stress state.
3. A method for forming a semiconductor device comprising:
providing a semiconductor substrate;
forming an insulating layer on a surface of the semiconductor substrate;
providing an at least partially relaxed silicon-germanium layer:
forming a silicon layer on the at least partially relaxed silicon-germanium layer form a pre-strained semiconductor layer.
bonding a pre-strained semiconductor layer to the insulating layer, wherein a <100> direction of the pre-strained semiconductor layer is aligned with a <110> direction of the semiconductor substrate;
removing the at least partially relaxed silicon germanium layer; and
forming a transistor on the pre-strained semiconductor layer, wherein the transistor is aligned along the <100> direction of the pre-strained semiconductor layer.
4. The method of claim 3 wherein the semiconductor device is characterized as being a silicon-on-insulator device.
5. The method of claim 3 wherein bonding of the pre-strained semiconductor layer to the insulating layer is performed by thermal wafer bonding.
6. The method of claim 3 wherein forming a transistor on the pre-strained semiconductor layer comprises aligning a source/drain axis of the transistor along the <100> direction of the pre-strained semiconductor layer.
7. The method of claim 3 wherein forming a transistor on the pre-strained semiconductor layer comprises aligning a source/drain axis of the transistor perpendicular to the <100> direction of the pre-strained semiconductor layer.
8. Method for forming a semiconductor device comprising:
providing a semiconductor substrate;
defining a <110> direction of the semiconductor substrate;
forming an insulating layer on a surface of the semiconductor substrate;
providing a pre-strained semiconductor layer on a SiGe layer;
defining a <100> direction of the pre-strained semiconductor layer;
bonding the pre-strained semiconductor layer to the insulating layer, wherein the <100> of the pre-strained semiconductor layer is aligned with the <110> direction of the semiconductor substrate;
cleaving the SiGe layer to leave a remaining portion of the SiGe layer on the pre-strained semiconductor layer; and
removing the remaining portion of the SiGe layer after cleaving; and
forming a transistor on the pre-strained semiconductor layer, wherein the transistor is aligned along the <100> direction of the pre-strained semiconductor layer.
9. Method for forming a semiconductor device comprising:
providing a semiconductor substrate;
forming an insulating layer on a surface of the semiconductor substrate;
providing an at least partially relaxed silicon-germanium layer; and
forming a silicon layer on the at least partially relaxed silicon-germanium layer to form a pre-strained semiconductor layer
bonding the pre-strained semiconductor layer to the insulating layer, wherein the crystal orientation of the pre-strained semiconductor layer is not aligned with the crystal orientation of the semiconductor substrate;
removing the at least partially relaxed silicon-germanium layer; and
forming a transistor on the pre-strained semiconductor layer, wherein a source/drain axis of the transistor is aligned along a crystal orientation of the pre-strained semiconductor layer that enhances current transport capability of a PMOS transistor.
10. The method of claim 9 wherein the semiconductor device is a silicon-on-insulator device.
11. The method of claim 9 wherein the crystal orientation of the semiconductor substrate comprises a <110> direction of the semiconductor substrate.
12. The method of claim 9 wherein defining a the crystal orientation of the pre-strained semiconductor layer comprises defining a <100> direction of the pre-strained semiconductor layer.
13. The method of claim 12 wherein forming a transistor on the pre-strained semiconductor layer comprises aligning a source/drain axis of the transistor along the <100> direction of the pre-strained semiconductor layer.
14. The method of claim 13 wherein forming a transistor on the pre-strained semiconductor layer comprises aligning a source/drain axis of the transistor perpendicular to the <100> direction of the pre-strained semiconductor layer.
15. The method of claim 9 further comprising polishing the pre-strained semiconductor layer after cleaving through the at least partially relaxed silicon-germanium layer.