Electrical Characterisation of Thin Insulating Langmuir Blodgett Films Incorporated in Metal-Insulator-Metal Structures
Renewed interest in the use of LB films as the passivating layer in electronic devices has led to our study of M-I-M structures incorporating such multilayers. Our initial studies concentrated on the Ag/LB/Ag system, silver being chosen for the electrodes due to its oxide free surface after evaporation and ω-tricosenoic acid for the LB material due to its ease of deposition . In these structures the LB film was found to be non-insulating giving junction resistances typically of the order of ohms (even with 40 layers of ω-tricosenoic acid) [2,3]. The conduction mechanism through these junctions was caused by damage incurred during the evaporation of the top silver electrodes. To obviate this problem a metal for the top electrode with a much lower evaporation temperature was reguired. Magnesium was chosen, since its evaporation temperature of 300°C coupled with its low mass number made it ideal for the purpose. The result from Ag/40 layers LB/Mg were very promising giving fully insulating junctions. The LB film thickness was then reduced progressively down to 10 layers of ω-tricosenoic acid (300 Å thick) with no loss in its integrity. Electrical characterisation of these junctions with Ag bottom electrodes, Mg top electrodes and LB film thickness from 10–2 layers of ω-tricosenoic acid has been undertaken.
- 3.N.J. Geddes, J.R. Sambles, D.J. Jarvis and N.R. Couch: Proc. of 3rd MED Conf., Washington (1986)Google Scholar