Mechanism of EL2 effects on GaAs field-effect transistor threshold voltages

Depending on the magnitude of the out-diffusion of the deep-donor EL2 during the post-implant anneal, the substrate barrier height increases. This in turn affects the depletion of donors on the channel side of the substrate junction, so that the voltage that is needed to pinch off the channel from the Schottky barrier is reduced. Threshold-voltage shifts of the order of less than 13 mV for devices with threshold voltages of −200 mV are predicted.