SELECTIVE GROWTH AND OTHER APPLICATIONS OF HYDROGEN-ASSISTED MOLECULAR-BEAM EPITAXY

The usefulness of atomic hydrogen in molecular beam epitaxy has been demonstrated, centering around selective growth. Atomic hydrogen is effective for low-temperature cleaning of substrates, surfactant effects such as restrain of island growth and suppression of the surface migration of the adatoms and selective growth on masked or V-grooved substrates. These effects are dependent on substrate temperatures. The selective growth of GaAs has been successfully demonstrated at the conventional growth temperature and growth rate with the aid of atomic hydrogen. The main mechanism of the selective growth is the re-evaporation of Ga and As from mask materials such as SINx or SiO2. Selective growth has also been observed on low-index crystal facets. On (111)A and (110) facets, no GaAs was deposited in the presence of atomic hydrogen, the flux of which is approximately the same as that of Ga. GaAs quantum wire structures have been fabricated on the substrates with V-shaped grooves. The efficient capture and confinement of carriers into wire regions have been observed by photolumenescence.