Chemically-assisted ion-beam etching of (AIGa)As/GaAa: Lattice damage and removal by in-situ Cl 2 treatment

Abstract We evaluated the lattice damage in Al 0.4 Ga 0.6 As/GaAs Single Quantum Well (SQW) structures caused by Chemically-Assisted Ion-Beam Etching (CAIBE) in comparison with Ion-Beam Etching (IBE) and wet etching. The damage was analyzed by measuring the Photoluminescence (PL) of the SQWs as a function of the etch depth. While IBE ( E kin =400 eV) causes a damaged region of 27 nm depth, BCl 3 /Cl 2 -CAIBE ( E kin =400 eV) damages to a depth of 10 nm. An in-situ Cl 2 -treatment (C1 2 -flow=6 sccm, T Substrate =120°C, p =3×10 −4 mbar, without plasma) allows a pure chemical removal of the surface layer which was damaged by CAIBE. This combined process facilitates anisotropic etching together with a lattice damage as low as with wet etching.