Dry-etching process for the fabrication of optoelectronic gratings in III-V substrates

We report a novel, three-step dry etching process for the fabrication of first-order diffraction gratings in III - V semiconductors. The process takes advantage of the etching of thin films of SiO2 and an organosilicon electron-beam resist (poly(3-butenyltrimethylsilane sulfone)) by the H2/CH4 plasma that is used to etch InP and its alloys. The new method significantly reduces wafer handling and eliminates the wet resist stripping step. The gratings were imaged with a scanning tunneling microscope.