Method of creating defect free high Ge content (>25%) SiGe-on-insulator (SGOI) substrates using wafer bonding techniques
View Patent ↗A method for achieving a substantially defect free SGOI substrate which includes a SiGe layer that has a high Ge content of greater than about 25 atomic % using a low temperature wafer bonding technique is described. The wafer bonding process described in the present application includes an initial prebonding annealing step that is capable of forming a bonding interface comprising elements of Si, Ge and O, i.e., interfacial SiGeO layer, between a SiGe layer and a low temperature oxide layer. The present invention also provides the SGOI substrate and structure that contains the same.
1. A SiGe-on-insulator (SGOI) substrate comprising:
a semiconductor substrate;
a buried oxide layer comprising a stack of a low temperature oxide and a high temperature oxide located on said semiconductor substrate; and
a fully relaxed SiGe layer having a defect density of about 10 4 to about 10 5 defects/cm 2 or less and a Ge content that is greater than 25 atomic % located atop said buried oxide layer, wherein said buried oxide layer and said SiGe layer are separated by an interfacial layer comprising elements of Si, Ge and O.
2. The SGOI substrate of claim 1 wherein said fully relaxed SiGe layer has a measured relaxation value of greater than 90%.
3. The SGOI substrate of claim 1 wherein said interfacial layer has a thickness from about 10 to about 50 nm.
4. The SGOI substrate of claim 1 wherein said fully relaxed SiGe layer has a thickness from about 5 to about 50 nm.
5. A semiconductor structure comprising:
a strained semiconductor layer located atop a SiGe-on-insulator (SGOI) substrate, said SGOI substrate comprising a semiconductor substrate, a buried oxide layer comprising a stack of a low temperature oxide and a high temperature oxide located on said semiconductor substrate, and a fully relaxed SiGe layer having a defect density of about 10 4 to about 10 5 defects/cm 2 or less and a Ge content that is greater than 25 atomic % located atop said buried oxide layer, wherein said buried oxide layer and said fully relaxed SiGe layer are separated by an interfacial layer comprising elements of Si, Ge and O.
6. The semiconductor structure of claim 5 wherein said fully relaxed SiGe layer has a measured relaxation value of greater than 90%.
7. The semiconductor structure of claim 5 wherein said interfacial layer has a thickness from about 10 to about 50 nm.
8. The semiconductor structure of claim 5 wherein said fully relaxed SiGe layer has a thickness from about 5 to about 50 nm.
9. The semiconductor structure of claim 5 further comprising at least one CMOS device located on said strained semiconductor.
10. The semiconductor structure of claim 9 wherein said at least one CMOS device is a FET.
11. The semiconductor structure of claim 5 wherein said strained semiconductor layer and said fully relaxed SiGe layer have identical surface crystallographic orientations.
12. The semiconductor structure of claim 11 wherein said surface crystallographic orientation comprises (100), (111) or (110).