Electronic behaviour and field emission of a-C:H:N/Si heterojunctions

Electronic properties of nitrogen doped hydrogenated amorphous carbon films deposited in an inductively coupled plasma enhanced chemical vapour deposition process by decomposition of methane (CH4) and nitrogen (N-2) are reported. In particular, the relation of these properties to the overall field emission performance of an a-C:H:N/Si heterojunction is considered. The heterojunctions have forward to backward rectifying current ratios of 3-4 orders of magnitude. The capacitance as a function of voltage (C-V) characteristics show negligible hysteresis, zero flat band voltage and response up to 13 MHz without loss of the typical depletion transition. The current as a function of voltage (I-V) of the metal (Au)/a-C:H:N/Si are consistent with Fowler-Nordheim type tunnelling of carriers from Si into a-C:H:N. The transition barrier is found to be similar to 0.07 eV. Which is very close to the previously reported electron emission barrier into vacuum from a-C:H:N. Correlation between the electron emission properties of a-C:H:N/Si heterojunctions and the electronic properties are presented. (C) 1998 Elsevier Science B.V. All rights reserved.