Selective area growth of compound semiconductors induced by electron-beam irradiation

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Epitaxy on a specific local area is one of the ultimate goals in crystal growth technology, and is expected to introduce a new dimension for design and fabrication of novel artificial semiconductor structures for physical studies and devices applications. Our approach is to induce difference in growth behavior between the two areas by local modification of substrate with irradiation of an electron beam, without exposure to undesirable ambients, such as air and etching gases.The growth procedure consists of (i) a 10-keV electron beam irradiation, with electron doses of 10^<17>-10^<19> electrons/cm^2, on specific areas of a GaAs surface at room temperature, (ii) thermal annealing of the substrate at the annealing temperature of 400-640ﾟC,and (iii) deposition of GaAs by chemical beam epitaxy at the growth temperature of 300-500ﾟC,using triethylgallium and cracked arsine as source gases. We have found that, for the GaAs deposition at 400ﾟC or higher, growth rate is significantly enhanced on the irradiated area, yielding a plateau-like GaAs object. Carbon content of the irradiated area is 10^<18>cm^<-3> or less, as estimated from secondary ion mass spectroscopy analysis.13EA03 : On the basis of these results, we have discussed that the observed selectivity arises from the removal of a native oxide layr on the GaAs substrate by the combination of electron beam irradiation and thermal annealing. Selective area epitaxy using AlGaAs oxide mask layrs has also been investigated.