Atomic layer deposition in nanotechnology applications

The self-limiting growth principle At. Layer Deposition (ALD) facilitates the deposition of conformal films on any size of substrates, including nano objects. ALD method can be used for prepn. of nanomaterials like nanotubes by using porous materials or nanofibers as templates, but more often it is used to modify nanomaterials. In this presentation the use of ALD for making and modifying nanomaterials is exemplified by two ways: deposition of thin films on inside walls of porous substrates and prepn. of nanotubes using nanofibres as templates. The materials deposited are oxide and metal films. High surface area substrates are of interest as capacitors in trench structure DRAM devices. Porous materials are challenge for ALD since the deposition times in flow-type reactors are usually unpractical long. Through porous substrates represent a different case and they can be coated fast if the precursors flows are forced to go through the pores. Through porous substrates coated with a metal film may be of interest in microelectronics, fuel cells, optics and membranes in sepn. The prepn. of nanotubes by ALD of a thin film on polymer nanofibers and firing of the fibers in air will be described. The nanofibers used have been cellulose, synthetic polymers fibers and electrospun polymer fibers. [on SciFinder(R)]