US 6,593,625 B2 · Relaxed SiGe layers on Si or silicon-on-insulator substrates by ion implantation and thermal annealing

Abstract

A method to obtain thin (<300 nm) strain-relaxed Si1-xGex buffer layers on Si or silicon-on-insulator (SOI) substrates. These buffer layers have a homogeneous distribution of misfit dislocations that relieve the strain, remarkably smooth surfaces, and a low threading dislocation (TD) density, i.e. <106 cm−2. The approach begins with the growth of a pseudomorphic Si1-x Gex layer, i.e., a layer that is free of misfit dislocations, which is then implanted with He or other light elements and subsequently annealed to achieve the substantial strain relaxation. The very effective strain relaxation mechanism operating with this method is dislocation nucleation at He-induced platelets (not bubbles) that lie below the Si/Si1-xGex interface, parallel to the Si(001) surface.

Claims46

Dependent claims

A semiconductor structure comprising:

a substrate;
a first single crystalline layer located atop said substrate;
a second highly defective single crystalline layer atop said first single crystalline layer, said secondly highly defective single crystalline layer comprising planar defects which serve as sources and sinks of dislocation loops;
a third single crystalline layer essentially of the same composition as said first layer and comprising threading dislocations terminating at the interface between this layer and the subsequent fourth layer on top of said second layer in form of misfit dislocation segments;
and
a fourth relaxed single crystalline layer having a lattice parameter different from said third layer.

3 more elements

Dependencies are inferred from the claim text.

Relaxed SiGe layers on Si or silicon-on-insulator substrates by ion implantation and thermal annealing

Life of this patent

Relaxed SiGe layers on Si or silicon-on-insulator substrates by ion implantation and thermal annealing

Life of this patent

Abstract

Claims46