GAAS DRY ETCHING USING ELECTRON-BEAM INDUCED SURFACE-REACTION

GaAs dry etching using a showered electron beam (EB) through Cl2 gas has been studied. The etching rate of EB-assisted etching is twice that of Cl2 gas etching, and the etching yield is estimated to be 130 atoms/electron. A GaAs pattern with a 0.3-mu-m linewidth has been obtained by using a resist mask. It was confirmed through measuring photoluminescence that the damage induced by EB-assisted etching is nearly the same as that caused by gas etching, and less than the damage induced by reactive ion beam etching or ion beam etching. A reverse dry etching technique is demonstrated whereby a surface layer of carbon formed on the substrate resulting from EB irradiation is used as a mask for EB-assisted etching. High-selectivity is obtained between the carbon mask and GaAs. Using this technique, a 0.6-mu-m linewidth reverse pattern is transferred.