Forming structures that include a relaxed or pseudo-relaxed layer on a substrate

1. A method of forming a semiconductor structure that includes a strained layer on a substrate which comprises: providing a strained semiconductor layer on a donor substrate; providing a thin, protective layer of semiconductor material on the strained layer; providing a receiving substrate; providing a glassy layer on the receiving substrate prior to bonding the donor substrate to the receiving substrate; bonding the donor substrate to the receiving substrate; transferring part of the donor substrate in the form of a layer to the receiving substrate to form a first structure that includes the transferred layer, the strained semiconductor layer, the protective layer and the receiving substrate; and transforming the transferred layer of the first structure to a further glassy layer by a heat treatment which also converts the strained semiconductor layer to a layer of relaxed or pseudo-relaxed semiconductor material and the protective layer to a layer of strained material.

2. The method of claim 1 , wherein the protective layer has a thickness of between about 100 Å and about 300 Å and is provided by epitaxially growth of the semiconductor material on the strained semiconductor layer.

3. The method of claim 1 , which further comprises removing the further glassy layer to expose the relaxed or pseudo-relaxed semiconductor layer.

4. The method of claim 3 , which further comprises providing a layer of a strained semiconductor material on the exposed relaxed or pseudo-relaxed semiconductor layer.

5. The method of claim 3 , wherein the relaxed or pseudo-relaxed layer is a SiGe layer, the protective layer is made of silicon, and which further comprises selectively etching and removing the SiGe layer to expose the strained silicon layer.

6. The method of claim 1 , wherein the donor wafer includes a zone of weakness that defines the layer to be transferred so that the donor substrate can be detached along the zone of weakness, wherein the donor substrate is fabricated by forming a porous layer on a crystalline carrier substrate and growing a crystalline layer on the porous layer, such that the porous layer comprises the zone of weakness of the donor substrate, and further wherein the donor substrate is detached along the zone of weakness by at least one of chemical etching or mechano-chemical etching.

7. The method of claim 1 , wherein the donor wafer includes a zone of weakness that defines the layer to be transferred so that the donor substrate can be detached along the zone of weakness, and wherein the zone of weakness is formed by implanting atomic species in the donor substrate and the donor substrate is detached along the zone of weakness by applying thermal or mechanical energy.

8. The method of claim 1 , which further comprises applying a bonding layer of material onto at least one of the protective layer or the receiving substrate prior to bonding the protective layer and the receiving substrate.

9. The method of claim 1 , wherein the first structure that is prepared is a Si/SiGeOI structure that includes a stressed Si layer, a relaxed SiGe layer, a SiO 2 glassy layer and the receiving substrate.

10. The method of claim 1 , which further comprises providing electrical components in the strained semiconductor layer.