Excellent Surface Morphology Research Articles

Liquid phase epitaxial growth of gallium arsenide on an etched substrate

A method is described for etching the surface of GaAs substrates with a Ga solution in situ immediately prior to epitaxial layer growth from the liquid phase. Layers grown by this procedure show excellent surface morphologies and electrical properties ( μ∼5100 cm 2 v-sec at 300°K for n∼ 7.8×10 16 cm 3 ). Advantages of the method and its applicability to epitaxial growth of other III-V compounds are discussed.

Liquid-phase epitaxial growth of thin GaAs layers from supercooled solutions

A liquid-phase epitaxial technique using supercooled solutions free from precipitates has been developed. Excellent surface morphology and a reproducible thickness control of GaAs layers within 7% have been obtained for layer thicknesses at around 0.6 μ. This technique is readily applicable to GaAs field-effect transistors (FET’s) and other devices.

Optical and electrical properties of Mn-doped GaAs grown by molecular-beam epitaxy

An isolated acceptor impurity is shown to be responsible for the ∼113-meV deep luminescence band which is frequently seen in GaAs layers grown by molecular-beam epitaxy. We establish that this center, which is also observed in melt-grown and solution-grown GaAs and which has often been associated with the presence of native defects, is due to Mn. The luminescence arises from donor-acceptor and conduction-band–acceptor recombination involving holes bound at the Mn acceptor. Electron paramagnetic resonance on Mn-doped layers shows that Mn is incorporated as an isolated defect with cubic symmetry. This result, coupled with the suppression of Mn-associated luminescence and electrical activation under Ga-rich growth conditions, indicates that Mn is incorporated primarily as a substitutional acceptor on Ga sites. Hole concentrations scale with Mn source temperature in a manner consistent with arrival-rate-controlled incorporation from a Knudsen effusion source. Room-temperature hole concentrations up to the 1018-cm−3 level can be achieved while maintaining excellent surface morphology. This suggests that Mn will be a useful dopant in the growth of junction structures by molecular-beam epitaxy.