Low Temperature Transfer of Aligned Carbon Nanotube Films Using Liftoff Technique

Carbon nanotubes (CNT) have been proposed for many electronic applications, such as field emitter, diode, transistors, integrated circuit interconnections and thermal interface material (TIM). The growth temperature of high quality CNT typically takes place at high temperatures. The high growth temperature causes significant difficulty in the integration of CNT to the many common material used in electronics, such as, metal, glasses and most polymers. We prepare the high-density aligned CNT film on the silicon/silicon dioxide substrate using a plasma-enhanced chemical vapor deposition (PECVD) method. The aligned CNT film is kept intact after the supporting silicon dioxide layer is removed by hydrofluoric acid (HF) solution. The "lifted off" CNT film can be transferred to various substrates at room temperature. This method avoids the problem caused by the high temperature process, and retains the CNT film quality. Thermal characterization indicates that the resistance of the transferred CNT film is comparable with that of as-grown CNT film. This method can be extended to many electronic applications, such as the fabrication of the field emitter, integrated circuit interconnect and sensors, that require CNT synthesis temperatures not compatible with the substrate material.