Selective area epitaxy of GaAs using very low energy Ga+ focused ion beam deposition combined with molecular beam epitaxial growth

A Ga focused ion beam (FIB) has been used to grow conducting n-type GaAs in areas defined by the FIB irradiation. A low energy (25-100 eV) mass separated Ga-69(+) FIB was supplied to a GaAs (1 0 0) substrate, simultaneously with Si and As-4 molecular beams. The FIB was rastered over a selected area of the substrate producing a square 200 mu m x 200 mu m mesa during growth. The 77 K Hall mobility and carrier concentration values of the grown GaAs layers showed that material quality improved as the ion energy was reduced from 100 to 25 eV. At 300 K a peak mobility of 2380 cm(2) V-1 s(-1) at a carrier concentration of 2.5 x 10(18) cm(-3) was achieved for the 25 eV ion grown sample.