Investigation of sputtered indium-tin oxide/silicon interfaces: ion damage, hydrogen passivation and low-temperature anneal

Abstract

Sputtered indium tin oxide (ITO)/Si contacts reveal a reduced interfacial barrier on n-Si and an increase on p-Si as expected from ion damage. Deep level transient spectroscopy (DLTS) identifies three electron traps (0.10, 0.19 and 0.25 eV) in n-Si and a single hole trap at 0.20 eV in p-Si with concentrations ≈ 2–5 × 10 12 cm −3. Pre-hydrogenation of wafers in a plasma greatly reduces the DLTS signal, offering first evidence of in-situ passivation of sputter damage by atomic hydrogen. Low-temperature anneal (180°C, 12–24 h) of the ITO sputter damage and influence of illumination during anneal appear to favor possible defect anneal by recombination-assisted processes.