Experimental and theoretical characterization of delta-doped quantum well field-effect transistors grown by gas-source molecular-beam epitaxy

An experimental and theoretical study has been made of a delta-doped quantum well field-effect transistor, (δQWFET), that realizes for the first time the high two-dimensional electron gas concentration, transconductance, saturation current density, and DC gain, and the very low output conductance that are expected for this device. The structure is made unique by the presence of quantum size effects that occur in both delta-doped barriers and the quantum well. The quantum size effects in the barriers and well can thus be tailored independently to suit specific FET requirements while still maintaining the advantage of a spatially confined electron gas. A complete DC characterization of this structure has been carried out using capacitance-voltage, Shubnikov-de Haas, and variable-temperature Hall measurements. A model incorporating quantum size effects has been developed and used as a basis for calculations