905 nm Wavelength Laser as a Means for In Situ End-point Detection of Dry Etching of AlxGa1-xAs on GaAs

摘要

A method has been developed for in situ end-pointdetection of etching of AlxGa1-xAs over GaAs. The resultsobtained with a conventional 670 nm and a new 905 nm infraredlaser during etching have been compared. Light from a 670 nmlaser was strongly absorbed in both GaAs and AlxGa1-xAsmaterials and no interference was detected. In contrast, incidenceof 905 nm wavelength infrared laser light on the materials causedsome interference with AlxGa1-xAs, and no interference withGaAs due to absorption. The results produced a noticeabledifference of signal patterns for etching of the two materials.End-point detection data with the 905 nm laser on variousAlxGa1-xAs compositions (i.e., x= 0.3-0.92) and different types(n- or p-AlGaAs) are also reported.