Eduction´s Position Control of the Incorporated Gallium in the Diamond-like Carbon Deposited by Focused-Ion-Beam Chemical-Vapor-Deposition

Summary form only given. Deposited materials by focused-ion-beam chemical-vapor-deposition (FIB-CVD) have a lot interesting material characteristics. It contains the gallium (Ga) because Ga is implanted by Ga⁺ FIB irradiation. Atomic ratios of the diamond-like carbon (DLC) deposited by using phenanthrene (C₁₄H₁₀) as a gas source for FIB-CVD is C : Ga = 95 : 5. And, it is noted that the incorporated Ga in DLC is segregated again from DLC by annealing treatment. By annealing treatments at approximately 400 degree C, the segregated Ga is appeared on the DLC surface in form of the sphere. However, Ga sphere is appeared on the random position of DLC surface. There have not yet been any reports concerning the method for the eduction´s position control of Ga contained in DLC deposited by FIB-CVD. So, the several experiments were carried out to examine the eduction process of incorporated Ga from the nanostructure made of DLC. As a result, we found that the eduction´s position control of Ga sphere could be achieved by via hole fabricated on the nanostructure using FIB-etching. In this experiment, DLC pillar was fabricated by a spot irradiation of 30 kV Ga⁺ FIB with a beam current of 8 pA. And a via hole was fabricated on the tip of DLC pillar by FIB-etching. Ga sphere was obtained on the tip of DLC pillar by 15 min annealing treatment at 350 C. Atomic ratio of Ga sphere formed by annealing treatment was C : Ga = 2.4 : 97.6. Furthermore, DLC wall structure was fabricated by FIB-CVD, and three via holes were fabricated by FIB-etching. By annealing this structure, we obtained Ga sphere on the top of DLC wall structure. In this way, we found that the Ga sphere was formed on the via hole inevitably. From these results, the Ga eduction mechanism is presume as follows; the incorporated Ga moves toward the via hole, Ga is accumulated in the via hole, Ga sphere is formed finally because Ga has the large value of the surface tension (720 - mN/m). In this way, we achieved the eduction´s position control of the incorporated gallium using the via hole. This technique is the utilizable technique as a junction technique such as a nano-bump technique to combine the nanoelectromechanical devices.