Multilayer Structure Comprising A Substrate and A Layer Of Silicon and Germanium Deposited Heteroepitaxially Thereon, and A Process For Producing It

Abstract

A multilayer structure, comprises a substrate and a layer of silicon and germanium (SiGe layer) deposited heteroepitaxially thereon having the composition Si 1-x Ge x and having a lattice constant which differs from the lattice constant of silicon, and a thin interfacial layer deposited on the SiGe layer and having the composition Si 1-y Ge y , which thin interfacial layer binds threading dislocations, and at least one further layer deposited on the interfacial layer.

1 . A multilayer structure, comprising a substrate and a layer of silicon and germanium (SiGe layer) deposited heteroepitaxially thereon having the composition Si 1-x Ge x  and having a lattice constant which differs from the lattice constant of silicon, the multilayer structure having a thin interfacial layer which binds threading dislocations deposited on the SiGe layer, the thin interfacial layer having the composition Si 1-y Ge y , and having a thickness of from 2 nm to 30 nm, and at least one further layer deposited on the thin interfacial layer. 
     
     
         2 . The multilayer structure of  claim 1 , wherein the concentration of germanium increases over the thickness of the SiGe layer. 
     
     
         3 . The multilayer structure of  claim 1 , which has an interfacial layer thickness of from about 2 nm to about 3 nm. 
     
     
         4 . The multilayer structure of  claim 1 , having a density of at most 1.5 E+4 threading dislocations/cm 2  on the surface. 
     
     
         5 . The multilayer structure of  claim 1 , having a density of at most 1 cm/cm 2  pile-ups of threading dislocations. 
     
     
         6 . The multilayer structure of  claim 1 , which has a surface roughness of at most 2 Å rms in a 1 μm×1 μm window. 
     
     
         7 . The multilayer structure of  claim 1 , which includes a relaxed heteroepitaxial buffer layer having the composition Si 1-z Ge z , which has been deposited on the thin interfacial layer, and a layer of strained silicon, which has been deposited on the relaxed heteroepitaxial buffer layer having the composition Si 1-z Ge z . 
     
     
         8 . The multilayer structure of  claim 1 , which includes a layer of strained silicon which has been deposited on the thin interfacial layer. 
     
     
         9 .- 20 . (canceled) 
     
     
         21 . The multilayer structure of  claim 1 , wherein x and y are equal, and the thin interfacial layer is deposited at a rate of ≦50 nm/min. at a temperature of 900 to 1100° C. 
     
     
         22 . A multilayer structure, comprising a substrate and a layer of silicon and germanium (SiGe layer) deposited heteroepitaxially thereon having the composition Si 1-x Ge x  and having a lattice constant which differs from the lattice constant of silicon, the multilayer structure having a thin interfacial layer which binds threading dislocations deposited on the SiGe layer, the thin interfacial layer having the composition Si 1-y Ge y  and having a thickness of from 2 nm to 30 nm, and at least one further layer deposited on the thin interfacial layer produced by a process comprising the steps of:
 providing a layer of silicon and germanium (SiGe layer) deposited heteroepitaxially on a substrate having the composition Si 1-x Ge x  and having a lattice constant which is different from the lattice constant of silicon, and depositing a thin interfacial layer having the composition Si 1-y Ge y  on the SiGe layer, which thin interfacial layer binds threading dislocations, and depositing at least one further layer on the interfacial layer.