CBE growth of InGaAs for optoelectronic applications

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In this work we studied the growth conditions Three different group III flux controls were of InGaAs single layer lattice matched to InP, tested: (1) pinhole (0.3—0.8 mm in diameter), (2) using TEGa, TEIn, TMIn and AsH3, in order to manual high precision leak valves without any investigate: (a) thickness and composition unifeedback; (3) automatic high precision leak valves formity; (b) role of different MO flux control with a feedback control to keep a constant pressystems on crystal quality; (c) effect of growth sure in the line connecting this valve to the effutemperature on growth rate and alloy composision cell. No carrier gas was used for metalorganic tion. transport. The effusion cell was common to all the The growth apparatus consisted of a standard four group III lines and specially designed in diffusion pumped VG 80H MBE, connected to a order to allow proper metalorganic premixing only pressure controlled gas system. While the group V at the end of the cell. gas line and furnace are standard, the group III To compare the different group III flux control, introduction system was entirely home made. The over 100 samples have been grown and analyzed growth was performed under an As2 flux of 5 X by DCXRD. The spectra of layers grown using 1014_3 x i0~mol/cm 2 s, at growth rates of 0.8—2 the pinhole were very reproducible, peaks of 50 sm/h and at substrate speed rotations of 20—45 arc sec FWHM were obtained, but the presence of rpm. Uniformity on 2 inch wafers has been meawider peaks and/or tails in most of the samples sured on an InGaAs 1.5 ~tm thick epilayer grown implies the onset of unwanted parasitic effects on both In-soldered and In-free mounted subalong the line. Some of the layers grown using the strates. Results are summarized in table 1. As the manual high precision leak valve showed narrow, maximum deviation results were always lower than even if structured, DC X-ray diffraction peaks 1% in thickness and 1.5% in composition, CBE (FWHM of 33 arc sec was obtained), but part of looks very promising from this point of view.