Ion beam induced interdiffusion at the InGaAs/InAlAs interfaces

Ion implantation induced interdiffusion at the In 0.53 Ga 0.47 As /In 0.52 Al 0.48 As quantum wells during post-implantation annealing has been investigated using Si, B and Al as implant ions. Interdiffusion at the heterointerface is monitered with the energy shifts in the photoluininescence peak from the InGaAs quantum wells. Enhanced shifts in the photoluminescence peak to higher energies (blue shifts) are observed for Si and Al ions, whereas enhanced shifts to lower energies (red shifts) are observed for B ions. In both cases, the shifts occur almost in the initial annealing stage (below 180s), and thereafter tend to level off. We interpret these behaviours in terms of the re-arrangement process of Ga, In and Al interstitials and vacancies created by ion implantation – damage-induced interdiffusion. Light ions (B) create In and Ga interstitials much more than Al interstitials, leading to enhanced In↔Ga interdiffusion (red shift), whereas heavier ions (Si, Al) create Al interstitials (which are most mobile in the crystal) sufficient enough to enhance Ga↔Al interdiffusion (blue shift).