SELECTIVE-AREA EPITAXIAL-GROWTH OF GAAS BY GAS-SOURCE MOLECULAR-BEAM EPITAXY USING METAL GALLIUM AND TRISDIMETHYLAMINOARSINE

We propose a novel method for realizing the selective-area growth (SAG) of GaAs using metal gallium, instead of carbon-containing group-III sources, such as trimethylgallium (TMGa). In order to eliminate the growth of GaAs on a SiO2 mask, trisdimethylaminoarsine (As[N(CH3)(2)](3), TDMAAs) was used as an arsenic source. The growth of GaAs on SiO2 was suppressed by increasing the substrate temperature and the TDMAAs beam-equivalent pressure (BEP). SAG was achieved at substrate temperatures of 550 degrees C and higher. A smooth surface with a (2 x 4) reconstruction was obtained under a specific TDMAAs BEP. The epitaxial growth rate of GaAs decreased along with increasing the TDMAAs BEP; eventually, etching of GaAs by TDMAAs occurred at 600 degrees C. The results show that SAG takes place due to the effect of an active species derived from TDMAAs on the re-evaporation of Ga adatoms from SiO2.