OPTICAL IN-SITU MONITORING OF WET CHEMICAL ETCHING

Optical in situ monitoring, exploiting the interference of monochromat ic radiation reflected from the surface being chemically etched and fr om the deeper interfaces of semiconductor layers, was utilized to moni tor the etch process of layered AlGaAs/AlAs/GaAs structures, The descr ibed method is applicable in controlled etching of heterostructures in order to terminate the etch process precisely and it is also suitable for analysis and diagnostics of epitaxially grown layers and for cali bration of etch rates. (C) 1998 John Wiley & Sons Ltd.