تأثير جسيمات ألفا في الخصائص الكهربائية لنبائط MIS : Au-Ta2O5-GaAs

Abstract EN

The paper aims to study the effect of alpha particles on the electrical properties of MIS:Au-Ta2O5-GaAs devices and on the electrical current transition mechanism.

The devices are prepared by deposing a layer of gold with a thickness of 1000 Å by using the thermal evaporation method under a pressure of 10-5 torr to form the upper gate of the MIS construction.

The prepared devices are irradiated with alpha particles from a 226 Ra source (0.5 Ci).

The irradiation is performed under room temperature with alpha energies of (1.2, 1.8, 3, 4, 5.1) MeV for different times of (0-30) min.

The irradiation solid angle was small to maintain the alpha particles normally incident on the devices.

The maximum energy (5.1 MeV) of the alpha particles is attenuated to lesser energies by situating polymer sheets with different thicknesses in front of the incident particles.

The energy loss and the range of alpha particles within the layers of the device; the gold (Au), the tantalum oxide(Ta2O5) and the gallium arsenide(GaAs), are calculated to determine the way of losing the alpha particles of their energies, the amount of the produced damage and the point where the maximum energy loss is taking place within the device.

The irradiation showed an effect on the electrical properties of the device, and this effect is found to be varied with the particles energy and the irradiation time.

The I-V characteristics showed that the current transition mechanism is Shottky for most of the cases of irradiation and Poole-Frenkel for some cases.

These characteristics also showed a permanent damage in the device at energies of (1.2 and 5.1) MeV, and a temporary effect at energies of 4 MeV, while there was no significant effect at energies of (1.8 and 3) MeV.