Comparison of OMVPE and MBE Grown AlGaAs/InGaAs PHEMT Structures

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δ-doped PHEMT structures commercially grown by OMVPE and MBE on 3 inch wafers were examined using contactless resistance, magneto-Hall, PR, PL, DXRD, RBS, SIMS, and electrochemical capacitance-voltage measurements, and 0.1 μm gate length devices were fabricated from them and then characterized. The electron mobilities in the OMVPE 2DEG were a little smaller than those in the MBE 2DEG, but were still excellent, and the carrier concentrations, which were > 2.5 × 1012 cm−2 at 77 K, were similar. The interface quality as measured by PR spectra was a little better in the MBE sample. Variation in the In areal density as determined by RBS was a little larger in the OMVPE wafer, but it was still less than 1 at%. The sheet resistance and the doping concentration as determined by SIMS and EC-V measurements showed the variation in the OMVPE wafers was slightly larger, but it was still considered to be small. PHEMTs fabricated from the most promising OMVPE wafer had gm's (753 mS/mm) that approached those for the MBE wafer (796 mS/mm) as did their fT's (115 versus 117 GHz). The variations in these parameters were also found to be slightly larger in the OMVPE wafers.