Surfactants control of surface process in gallium indium phosphide and gallium arsenide epitaxial layers grown by organometallic vapor phase epitaxy

The addition of the surfactants during growth using conditions that would otherwise produce highly ordered GaInP, results in disordered materials. The resulting low temperature photoluminescence (PL) shows an increase in band gap energy as the surfactant/III ratio in the vapor increases. The surfactants also change the surface reconstruction, reducing the thermodynamic driving force for ordering, as observed by surface photo-absorption measurements.; Atomic force microscopy reveals that Bi concentration in the vapor of (Bi/III)_v = 1.65 × 10−2 increases the [110] step velocity by at least an order of magnitude and significantly reduces surface roughness. The addition of Sb [(Sb/III)_v = 1.2 × 10−2] also produces smooth surface morphology. Higher Sb/III ratio [(Sb/III)_v = 6.4 × 10−2], however, produces surface undulations with a period of ∼120 nm. No step structure change occurs when a high As/III ratio [(As/III)_v = 0.88] is added during growth.; With the addition of Bi, layers grown at low growth rates [r_g = 0.3–0.47 mm/hr] spontaneously form lateral compositional modulation in the [110] direction. PL emission is observed to be strongly anisotropic. The growth rate is found to strongly affect the compositional modulation. The process controlling the amplitude appears to be kinetically limited.; The results of a study on the effects of the isoelectronic surfactant Sb on doping in GaAs are presented. The addition of a small amount of triethylantimony during growth is found, using SIMS analysis, to increase the Zn and In concentration in the solid. The amount of Sb introduced into the solid is only 2–3 × 1017 atoms/cm3. The addition of Sb does not affect the concentration of Te or P.; Te-doped GaInP epitaxial layers were grown in an effort to clarify the Te disordering mechanism. As the growth rate was decreased, with a corresponding decrease in measured step velocity, the degree of order was observed to increase, in support of this kinetic model. GaInP layers grown at higher temperatures were observed to become much less ordered. Analysis of the study indicates that the effect is due mainly to the effect of temperature on step velocity. The direct correlation between the step velocity and the degree of order, confirms that Te disorders GaInP for kinetic reasons.