| The growth and surface chemistry of III-V alloys during metalorganic vapor- phase epitaxy has been investigated. In particular, the structure of ordered and disordered indium gallium phosphide (001) surfaces, the growth of indium gallium arsenide nitride and the growth of gallium arsenide on silicon (100) have been examined.; Ordered and disordered InGaP (001) films were studied by low energy electron diffraction, reflectance difference spectroscopy, and x-ray photoemission spectroscopy. Both alloy surfaces were covered with a monolayer of buckled phosphorus dimers. Ordered InGaP (001) appeared indium rich, and exhibited a reflectance difference spectrum like that of InP (001). These results support a model whereby the strain energy on the ordered InGaP surface is reduced by aligning the group III atoms in alternating [110] rows, with the indium and gallium bonding to the buckled-down and buckled-up phosphorus atoms, respectively.; The metalorganic vapor-phase epitaxy of In0.06G0.94As 1-xNx at 550°C and with x = 0.00 to 0.02 has been examined using nitrogen trifluoride as the N source. The solid N/(N+As) ratio increased linearly with the gas-phase N/(N+As) ratio up to a limit of 2.0% nitrogen in the film at a gas N/(N+As) = 0.35. No further increase in nitrogen content could be achieved at a growth temperature of 550°C unless the feed rate of the group III sources was reduced. It was shown that NF3 addition to the reactor results in a growth rate decrease of 40% with increasing NF 3 feed rate up to 3.0x10-4 mol/min (N/(N+As) = 0.35). Further addition of NF3 did not affect the growth rate, but caused the surface roughness to rise rapidly from 0.1 to over 1.0 nm. Results indicate that the increased roughness was due to fluorine etching of the adsorbed group III elements.; The selective area, metalorganic vapor-phase epitaxy of gallium arsenide on silicon substrates was investigated. A two-step growth method was used to deposit the GaAs films with a optimum nucleation temperature of 400°C. Layers nucleated at 350°C or below were found to be poly-crystalline whereas those nucleated at 400°C and above were single crystal. The x-ray diffraction full-width-at-half-maximum decreased from 890 to 775 arc-sec for a 1.0-mum-thick GaAs layer grown on unpatterned versus patterned Si (WO) wafers. The 77K photoluminescence peak position was 1.489 and 1.498 eV for a 1.0-mum-thick GaAs layer on unpatterned and patterned substrates, respectively. In summary, we find that selective area growth of GaAs on Si improves film crystallinity while reducing the in plane strain in the film by 35%. |
