A computer controlled chemical bevel etching apparatus: applications to Auger analysis of multi-layered structures

Analysis of thin layer structures can be achieved by chemically etching a b evel and subsequently analysing the surface. However non-linear bevels ofte n result due to differing etch rates of the materials lending to incorrect analysis results, We report on a computer controlled stepper motor reactor whereby the specimen is lowered into the etchant at a rate which compensate s for the different etch rates of the various layers constituting the sampl e. The apparatus is used to produce linear bevels of various magnifications on GaAs/AlGaAs heterostructures. The etchant of H3PO4/H2O2/H2O is used for bevel preparation capped by a water layer to suppress the meniscus. Applic ation of the technique to Multi Quantum Wells (MQW) and Bragg diffraction l ayers is shown. The depth resolution of the bevelled samples are analysed b y AES and a comparison is made to conventional ion sputtering techniques. ( C) 1999 Elsevier Science B.V. All rights reserved.