Uniform and abrupt InGaP/GaAs selectively doped heterostructures grown by MOVPE for HEMT ICs

Abstract Uniform and abrupt Si-doped InGaP/GaAs selectively doped heterostructures are grown by atmospheric-pressure metalorganic chemical vapor deposition, and the feasibility of the material system for HEMT ICs is demonstrated for the first time. The uniformities of donor concentration and thickness of Si-doped InGaP layers are ±4.5% and ±1.5%. These values are small enough for IC applications. The mobility at 4.2 K and the two-dimensional electron gas concentration obtained from Shubnikov-De Haas oscillation measurements are 89,300 cm2/V·s and 8.9×1011 cm−2 for samples with a spacer thickness of 5.5 nm. HEMT IC structures were grown to evaluate the device characteristics. It was shown that enhancement- and depletio-mode HEMTs can be fabricated on the same wafer by selective etching technique. The characteristics of the transistors exhibit no instability at 77 K.