A Combined Sputter Profiling/Ion Channeling Technique for Measuring Defect Depth Distributions

The ideal configuration of a lattice mismatched, thick film, semiconductor heterostructure (i.e. GaAs/Si) consists of a nearly dislocation free surface layer and a heavily defected interfacial region. Ion backscattering combined with channeling can be an excellent probe of this structure as it directly provides a depth profile of dislocation density in the high density region (>10 sup 8 /cm sup 2). We have tested the validity of this technique by extracting the defect density as a function of depth for GaAs/Si samples of varying thickness.