RTCVD synthesis of carbon nanotubes and their wafer scale integration into FET and sensor processes

• Autores: Iñigo Martin Fernández
• Directores de la Tesis: David Jimenez Jimenez (dir. tes.), Philippe Godignon (dir. tes.)
• Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2010
• Idioma: inglés
• Tribunal Calificador de la Tesis: María Teresa Martínez Fernández de Landa (presid.), Adrian Bachtold (secret.), Enric Bertran Serra (voc.)
• Materias:
  • Ciencias tecnológicas
    • Tecnología electrónica
• Enlaces
  • Tesis en acceso abierto en: DDD
• Resumen

  • Carbon nanotubes (CNTs) are tubular molecules which diameters may be smaller than one nanometre and which walls are formed of single carbon atoms layers that are arranged in a honey comb lattice. Because of their high aspect ratio, they may be considered as one-dimensional materials since their length is typically in the order of the micrometers, in combination with their properties, which are conferred by their structural arrangement, CNTs are a very attractive material for a wide range of applications. In the frame of micro- and nanotechnology, CNTs have been demonstrated to be very promising for the fabrication of devices and systems for nanoelectronics, sensors or NEMS. However, standardised processes for their fully controlled synthesis and their successful integration into those systems are still challenging. This thesis was conceived to advance on the wafer scale integration of CNTs into micro- and nanodevices. Performed work dealt with process engineering, device design, device fabrication and device characterization. Two major goals were pursued: (i) to acquire the knowhow on the synthesis of CNTs by rapid thermal chemical vapour deposition (RTCVD) to develop recipes to synthesize certain in structure CNTs and certain in morphology CNT layers, and (ii) the wafer scale integration of CNTs into devices with different functionalities and technological processes by conventional fabrication processes. Despite the inherent problematic of the technological process developments, most of the initially foreseen goals were fulfilled. The CNT synthesis was achieved by conventional (mainly iron and nickel) and by nonconventional (platinum) catalyst materials. It is remarkable how the CNT RTCVD synthesis processes were standardized at 4 inch wafer scale for either low density of SWCNT layers or for dense, vertically aligned MWCNT layers, since the CNT synthesis is normally performed at chip level. Regarding the wafer scale integration of the CNTs, two main processes were optimised. On the one side, SWCNTs were integrated in the fabrication of CNT-FETs. 10,000 CNT-FETs were successfully fabricated on 4 inch wafer in sole fabrication process. On the other side, dense arrays of CNTs were integrated into devices based on metallic electrodes that had previously been demonstrated for bio-electrochemical sensing. These electrodes improved the fabrication yield and the electrochemical characteristics with respect to the previous designs. Presented results are a step forward to the VLSI of CNTs. The developed processes are of interest in the field of nanoelectronics, in the field of bio-electrochemical sensing, for the fabrication of optoelectronic devices and for the fabrication NEMS.