Characterization of subsurface damage in GaAs processed by Ga+focused ion‐beam‐assisted Cl2etching using photoluminescence

摘要

Subsurface damage in GaAs processed by a Ga+focused ion‐beam‐assisted Cl2etching is studied by photoluminescence (PL) measurement. The PL intensity of the processed sample decreased to (1)/(30) – (1)/(40) compared to that of the unprocessed sample. The recovery of PL intensity by a step removal of the damaged layer is observed as a function of the removed layer thickness. The removal of a 0.7‐mgr;m‐thick surface layer enables the PL intensity to be recovered perfectly, which leads to the postulate that the damaged layer thickness is 0.7 mgr;m at least, which is much larger than the ion range (about 0.01 mgr;m). The recovery of PL intensity is analyzed on a one‐dimensional model in the direction normal to the sample surface. Computer simulations of PL intensity are carried out. The calculated result fully explains the experimental PL intensity recovery as a function of the removed layer thickness, which gives the profile of subsurface damage in the sample.