Forming structures that include a relaxed or pseudo-relaxed layer on a substrate
A method for forming a structure that includes a relaxed or pseudo-relaxed layer on a substrate. The method includes the steps of growing an elastically stressed layer of semiconductor material on a donor substrate; forming a glassy layer of a viscous material on the stressed layer; removing a portion of the donor substrate to form a structure that includes the glassy layer, the stressed layer and a surface layer of donor substrate material; patterning the stressed layer; and heat treating the structure at a temperature of at least a viscosity temperature of the glassy layer to relax the stressed layer and form the relaxed or pseudo-relaxed layer of the structure.
1. A method for relaxing a layer of a strained material on a substrate which method comprises:
providing an elastically stressed layer on a first substrate;
providing a first glassy layer on the stressed layer or upon a second substrate;
bonding the first and second substrates together with the stressed layer and first glassy layer therebetween;
removing the first substrate to obtain a structure comprising the stressed layer, first glassy layer and second substrate;
providing a second glassy layer on the stressed layer; and
heat treating the structure at a temperature close to or higher than the viscosity temperature of one or both of the glassy layers to convert the stressed layer to a relaxed or pseudo-relaxed layer.
2. The method of claim 1 , wherein the heat treating temperature is about 1150 to 1500° C.
3. The method of claim 1 , wherein the heat treating temperature is about 1150 to 1200° C.
4. The method of claim 1 , wherein the stressed layer is provided by growing the layer on the first substrate.
5. The method of claim 1 , wherein the first glassy layer comprises a viscous material having an associated viscosity temperature, and the heat treating is conducted at or above the viscosity temperature.
6. The method of claim 1 , wherein the second glassy layer is provided by removing a portion of the first glassy layer and leaving a surface layer of the first substrate on the structure, applying a controlled treatment to transform at least a portion or all of the surface layer to a viscous material having an associated viscosity temperature, and the heat treating is conducted at or above the viscosity temperature.
7. The method of claim 6 , which further comprises growing a further layer on the structure.
8. The method of claim 7 , which further comprises removing the second glassy layer before growing the further layer.