Inverted thermal conversion—GaAs, a new alternative material for integrated circuits

We developed a new type of GaAs which exhibits inverted thermal conversion (ITC), i.e., it converts from conducting to semi-insulating upon annealing at about 850 °C. In device fabrication, its low resistivity, prior to high-temperature processing, differentiates ITC from the standard semi-insulating GaAs. The ITC characteristics are obtained through control of the concentration of the midgap donor EL2 based on heat treatment and crystal growth modification. Thus, EL2 does not exist in the conducting state of ITC GaAs. Conversion to the semi-insulating state during 850 °C annealing is caused by the formation of EL2 consistent with our earlier proposed EL2 model.