Quantum storage effects in n-AlGaAs/GaAs heterojunction FETs with embedded InAs QDs and localized states induced by Ga-FIB implantation

Quantum storage effects have been studied on novel n-AlGaAs/GaAs heterojunction field-effect transistors (FETs) where electron trapping sites, such as localized states induced by Ga-FIB implantation or self assembled InAs quantum dots (QDs), are embedded between the gate and two-dimensional (2D) electron channel. Charging characteristics involving different types of trap levels distributed spatially have been studied by analyzing the current–voltage (I–V), capacitance–voltage (C–V), and frequency-dependent conductance (G) measurements. Information on the trapping mechanisms of electrons and the distribution of trapping sites has been extracted. We found that the charge injection and extraction on single-electron trapping sites has influence on the single-electron memory operation including the quantized threshold voltage (Vth) shift effects.