In situ resistivity studies of 200 MeV 107Ag 14+-ion irradiated n-GaAs epitaxial layers

Abstract

The effect of 200 MeV 107Ag 14+-ion irradiation on the electrical transport behavior of Si-doped n-GaAs epitaxial layers has been investigated employing in situ resistivity measurements. The n-GaAs epitaxial layers grown by metallorganic chemical vapor deposition method have carrier concentrations of 3×10 15, 3×10 16 and 3×10 17 cm −3. The fluence of 200 MeV 107Ag 14+ ion is varied from 2×10 8 to 5×10 11 ions cm −2. It is observed that in all the three epitaxial layers, resistivity initially remains constant up to a critical fluence. After this critical fluence, which depends on the initial carrier concentration in the layer, there is a rapid increase in resistivity with fluence. The swift heavy-ion irradiation-induced deep-level defects, which trap the free carriers and causes the mobility degradation, are responsible for enhancement in resistivity. The swift heavy ion traversing through the semiconductor, transfers its energy via nuclear and electronic energy-loss mechanisms. The implications of these energy-loss processes inside n-GaAs have been discussed.