GaInP/InGaAs/GaAs graded barrier MODFET grown by OMVPE: design, fabrication, and device results

Ga/sub x/In/sub 1-x/P/Ga/sub y/In/sub 1-x/As/GaAs Modulation Doped Field Effect Transistors (MODFET's) with a pseudomorphic barrier and a pseudomorphic channel were grown by Organo Metallic Vapor Phase Epitaxy (OMVPE). This material system is promising for advanced MODFET's on GaAs for high frequency and power applications, because of the large discontinuity in the conduction band, advantages in the processing and the capability to increase the energy separation between the bottom of the conduction band and Fermi level by compositionally grading the barriers. Record 2-dimensional Electron Gas (2-DEG) carrier densities of 3.1/spl middot/10/sup 12/ cm/sup -2/ for single-sided MODFET's were measured. Measured RF power at 10 GHz for 0.25 pm devices was /spl ges/0.4 W/mm. For the first time cutoff frequencies f/sub T/ and f/sub max/ exceeding 105 and 188 GHz, respectively, were obtained for this material system with 0.1 /spl mu/m gate-length MODFET's.