A study of ageing effect at elevated temperature of flexible silicon diodes integrated using conductive adhesives

Abstract

A simple fabrication scheme of using silver-filled conductive tape to form flexible single crystalline Si–Pd Schottky diodes on a polymer substrate has been studied and reported previously. In this investigation, we studied the long term thermal stability of these flexible diodes on polymer annealed at 80°C in open air for 1year. The I–V characteristics of the diodes were measured periodically. We found that the barrier height of the Si–Pd diodes remained relatively unchanged at 0.795eV±0.003 with an n-factor of 1.03±0.03, and a series resistance of ∼110Ω for diodes with a 950μm diameter, which are almost identical to the values before annealing. The integrated structure stayed flexible to a similar curvature after 1year. The stability of silver-filled conductive tape was investigated separately over the same period of time and under the same conditions. The resistance of two conductive tapes was found to quickly decrease from high initial values to significantly lower values, and remained constant over the course of the investigation. Based on these results, we conclude that this simple bonding technique of using conductive tape to fabricate flexible devices can be of useful value in practical applications.