Low temperature selective growth of GaAs quantum wires by modulated flux chemical beam epitaxy

We report that low-temperature selective growth of GaAs on GaAs(100) partially masked with SiN_x and on nonplanar patterned GaAs(100) by employing a modulated flux method of chemical beam epitaxy (MFCBE), where triethylgallium, trimethylgallium, arsine, and monoethylarsine are used. To achieve MFCBE, group III and V source materials were alternately fed into the growth chamber with and without evacuation period between each source supply. The growth selectivity of the GaAs layer by MFCBE was significantly enhanced compared to that of the layers grown by the continuous beam method. Furthermore, the surface morphology of GaAs layers grown by MFCBE was greatly improved under the same growth conditions. The improvement of selectivity of samples grown by MFCBE is attributed to a decrease of catalytic decomposition of metalorganic compounds on the SiN_x masks during evacuation and group III source supply periods. Our results also demonstrate that MFCBE can be a very powerful method for growth of ideal quantum wire structures. © 1997 American Vacuum Society.