Ion implantation into strained-layer superlattices

Abstract

Studies are presented of the structural and electrical properties of strained-layer superlattices (SLSs) after ion implantation and controlled-atmosphere annealing. GaAsn 0.2P 0.8/GaP and In 0.2Ga 0 8 As/GaAs SLS structures with 100 to 250Åthick layers were implanted with Be, N, Si or Zn, and analyzed by ion channeling and backscattering, X-ray diffraction, cantilever beam bending and Hall effect measurements. Implantation introduces compressive stresses comparable to the as-grown levels in SLSs; however, the SLS structures can often be retained in their coherent, epitaxial state after implantation and annealing. Disorder production, annealing and dopant activation are similar for SLSs to that for GaP and GaAs bulk alloys. At sufficiently high fluences (≳10 15/cm 2) and ion mass (Si, Zn), ion beam mixing decreases the composition modulation and Zn diffusion produces additional layer alloying beyond the ion range. Acceptor dopant activation and simple device structure formation have been demonstrated.