Patent ID: 7445977

Claim:
A method of forming a SiGe-on-insulator substrate comprising: forming a low temperature oxide at a deposition temperature of about 450° C. or less atop a structure that comprises a fully relaxed SiGe layer having a peak-to-peak roughness of less than 10 nm and a thickness from about 500 to about 100 nm located on a sacrificial substrate, said fully relaxed SiGe layer further has a measured relaxation value of greater than 90% and comprises a lowered graded portion and an upper relaxed portion, wherein said lower graded portion comprises a low Ge content region having 10 atomic % or less Ge in proximity to a surface of said sacrificial substrate, a middle region in which the Ge content increases in a stepwise manner, and an upper region having a Ge content that is greater than 25 atomic %; first annealing said structure including said low temperature oxide at a first temperature of from about 600° to about 700° C. for a time period from about 300 to about 1000 minutes to form an interfacial layer comprising elements of Si, Ge and O between the low temperature oxide and said SiGe layer; providing an implant region by ion implanting hydrogen within said fully relaxed SiGe layer; cleaning said low temperature oxide and a semiconductor substrate within an agent that forms a hydrophilic surface on each material; bonding said hydrophilic surface of said low temperature oxide to said hydropholic surface of said semiconductor substrate, wherein said bonding comprises contact bonding at nominal room temperature to form a bond between said hydrophilic surface of said low temperature oxide and said hydrophilic surface of said semiconductor substrate, a second anneal at a second temperature of from about 225° to about 350° C. to strengthen said bond, and a third anneal performed at a third temperature that is greater than the second temperature and of from about 485° to about 550° C. to cause separation at said implant region within said fully relaxed SiGe layer, whereby said sacrificial substrate and a portion of the fully relaxed SiGe layer are removed, and wherein said second and third annealing are performed without breaking a vacuum; and re-annealing the structure at a fourth temperature that is greater than the third temperature and is from about 600° to about 700° C. to form a SiGe-on-insulator (SGOI) substrate that comprises the semiconductor substrate, said low temperature oxide located on said semiconductor substrate, and said 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 low temperature oxide, wherein said low temperature oxide and said fully relaxed SiGe layer are separated by said interfacial layer; thinning the fully relaxed SiGe layer, said thinning step comprises chemical mechanical polishing, ion beam etching or a combination of high pressure oxidation and wet etching; and forming a strained semiconductor layer atop the fully relaxed SiGe layer.