Barrier height modification of Au/n-Si Schottky structures by swift heavy ion irradiation

Influence of 120 MeV 107Ag7+ ion irradiation on current-voltage (I-V) characteristics of Au/n-Si(1 0 0) Schottky diodes as a function of fluence is investigated. The irradiation fluence was varied from 5 × 1010 to 1 × 1013 ions cm−2. By systematically varying the ion fluence we can control the variations in various parameters of the Schottky diodes. The ideality factor increases from a value 1.1 to 1.3 with increasing fluence upto 5 × 1011 ions cm−2. After this as fluence increases to 5 × 1012 ions cm−2, ideality factor becomes 1.28. The Schottky barrier height (SBH) decreases from a value of 0.82 eV for the unirradiated diode to 0.72 eV for the diode irradiated with a fluence of 5 × 1010 ions cm−2. After this SBH increases to a value 0.77 eV and then remain constant upto a fluence 1 × 1013 ions cm−2. The basic energy loss mechanism of swift heavy ion (SHI) at the metal-semiconductor (MS) interface is used to explain the change in Schottky diode parameters. After an initial fluence of 5 × 1010 ions cm−2, the role of electronic energy loss in modification of interface states has been envisaged in relation to the immunity of SBH over a wide fluence range.