Electrical behaviour of metal/a-C/Si and metal/CN/Si devices

Electrical characterisation of metal/carbon/Si devices was performed. Amorp hous carbon films rich in sp(3) bonds were grown onto n-type Si substrates by RF magnetron sputtering at room temperature. Different deposition condit ions were used to create different sp(3) and sp(2) configurations in order to examine their influence on the performance of electronic devices. Suitab le metalisation was used to fabricate devices, which were then characterise d electrically. Electrical characterisation using I-V, C-G-V and G-omega te chniques showed temperature dependent currents through the devices which in crease rapidly when forward bias is applied. This behaviour was found to be dependent on the sp(3)-sp(2) contents of the films. The devices behaved li ke metal-insulator-semiconductor diodes with a defect insulator resulting i n creating thermally activated currents through the devices. The effect of nitrogen introduced in the growth process to produce carbon nitride films w as also examined. Different amounts of nitrogen were used and the same char acterisation process has been used for a variety of samples. The films were nearly perfect insulators and the corresponding devices showed a clear MIS behaviour. Thus, the room temperature magnetron sputtering technique produ ced films, with electronic properties dependent on the C-C bonding configur ation. Moreover it is shown that the nitrogenated films made under certain conditions can be used as insulators in devices. (C) 1999 Elsevier Science Ltd. All rights reserved.