Selective Growth Method of Carbon Nanotubes by Chemical Vapor Deposition

Carbon nanotubes (CNTs) are potentially useful for developing functional nanodevices such as thermal probes, flow sensor arrays, and AFM probes. Controlling the growth position of CNTs grown by chemical vapor deposition (CVD) is crucial to fabrication of these nanodevices. We propose an easy, non-lithographic process of making CNT sensor probes using CVD. Growth positions of CNTs were precisely controlled by depositing a patterned barrier layer above the catalyst layer. Then, the CNTs were grown from the exposed catalyst layer using CVD. This method is easily applied to assembling bridged CNTs. We used focused ion beam etching to remove the barrier layer and expose the catalyst membrane. Through the proposed method, we made a bridge of CNTs at the tip of a Si edge. This type of bridge can be used as the nanoprobes for local sensing of physical properties.