Studies of GaAs surface roughness and organic masks resistance depending on the ion-beam energy

Summary

The development of A^III–B^V semiconductor surfaces exposed to ion-beam irradiation in the ion energy range from 100 to 1000 eV and the ion current density of 1 mA/cm² (max) is investigated. The ion-beam etching with an ion energy of 1 keV results in sharp cones and needles on the semiconductor surface due to the surface contamination and unevenness. Etching with ion-beam energies in the order of 300 eV and with etch rates higher than 1000 Å/min produces relatively even GaAs surfaces. In case of reactive gases (i.e. CCl₂F₂ and the mixture of CCl₂F₂+Ar) ion-beam etching results in significantly higher etch rates; however, the mask residue contains Cl and F. In studies on the ion-beam resistance of organic masks selectivities as high as 13:1 for the photoresist CM-79 with an ion energy of 180 eV and an ion current density of approximately 0.3 mA/cm² were achieved.