EXCESS ARSENIC IN GAAS GROWN AT LOW-TEMPERATURES BY MOLECULAR-BEAM EPITAXY

The structural properties of GaAs grown at low temperatures by molecul ar beam epitaxy (LTMBE GaAs) were studied. The excess arsenic atoms in LTMBE GaAs exist in the form of arsenic interstitial couples (i,e, tw o ns atoms share the one host site), and cause an increase in the latt ice parameter of LTMBE GaAs. Annealing at above 300 degrees C, the ars enic interstitial couples decomposed, and As precipitates formed, resu lting in a decrease in the lattice parameter.