Two-dimensional electron gases in delta-doped GaAs/In0.25Ga0.75As/GaAs heterostructures

Delta-doped (δ-doped)GaAs/In0.25Ga0.75As/GaAs strained-layer modulation-doped field-effect transistor (δ-SMODFET) structures grown by the low-pressure metalorganic chemical vapor deposition (LP-MOCVD) technique have been studied for the first time. The δ-doped GaAs, adopted as the electron supplier, was obtained by a stop-growth process so that a very thin and heavily doped layer (1.9×1013 cm−2) can be realized. Experimental results show that a structure with an 80 Å In0.25Ga0.75As layer as the active channel and an 80 Å spacer layer demonstrated the highest two-dimensional electron gases mobility of 26 800 cm2/V s. This structure is easy to achieve by the LP-MOCVD method because the growth of AlGaAs is avoided and is promising for high performance FETs.