Strained N–Ga0.7Al0.3As/InxGa1-xAs/GaAs Modulation-Doped Structures

Abstract
Strained N–Ga0.7Al0.3As/In x Ga1-x As/GaAs modulation-doped structures were successfully fabricated. Also, a high concentration of two-dimensional electron gas (2DEG) (about 2×1012cm-2) was found to accumulate at heterointerfaces. Upon increasing the In composition in the InGaAs layer, the 2DEG concentration increased and the mobility decreased. Thus, a modulation-doped structure with In0.23Ga0.77As at room temperature has the lowest sheet resistance (about 500 ohms); this is two thirds of that for a conventional modulation-doped structure. The proposed structure is promising for field effect transistors with low channel resistances.