Degradation of GaN Conductivity Under Irradiation with Swift Ions

We present the results of investigation of radiation hardness of GaN epitaxial layers grown on sapphire substrate. Samples were irradiated with swift Ni, Ag and Au ions at room temperature. Electric and structure response to irradiation has been carried out by employing in situ measurements of electrical resistivity of irradiated samples. Drastic raise of sheet resistance with the ion fluence increase was found. Nuclear energy loss plays a significant role in ion-beam induced resistivity change since they determine the formation of point defects by a decelerating ion. Electronic energy loss despite its much higher value is believed to be much less important in conductivity reduction. Device characteristics degradation is mainly caused by point defect formed by cosmic radiation.