Conductive polymer films for microbolometer applications


In order to maximize the responsivity of a thermal detector, the detector is often fabricated on a thin membrane which is suspended over a substrate. Maximizing responsivity requires minimizing the thermal conductance and heat capacity while keeping the thermal time constant below the bandwidth of the system; maximizing the temperature coefficient of resistance (TCR) of the sensor materials, and reducing system noise. Uniformity of the detector elements greatly impacts the performance of a focal plane array. We report here a new material for IR bolometer applications. The material is a polymer film which has been made conductive by ion implantation. Implanted films which have a thickness of 1500 angstrom may be patterned by conventional photoresist processes to form small geometry elements with dimensions of 10 to 50 micrometers. Suspended conducting polymer bridges are then formed from the implanted films by etching of a sacrificial layer of silicon dioxide. High quality films with resistivities from 400 ohms/square to 10 megaohms/square can be produced by the ion implantation technique. Temperature coefficient of resistance (TCR) as a function of implantation energy and film resistivity are presented.


Physics, Astronomy, and Materials Science

Document Type

Conference Proceeding


Publication Date


Journal Title

Proceedings of SPIE - The International Society for Optical Engineering