Fabrication and characterization of boron-doped nanocrystalline diamond-coated MEMS probes

Abstract

Fabrication processes of thin boron-doped nanocrystalline diamond (B-NCD) films on silicon-based micro-and nano-electromechanical structures have been investigated. B-NCD films were deposited using microwave plasma assisted chemical vapour deposition method. The variation in B-NCD morphology, structure and optical parameters was particularly investigated. The use of truncated cone-shaped substrate holder enabled to grow thin fully encapsulated nanocrystalline diamond film with a thickness of approx. 60 nm and RMS roughness of 17 nm. Raman spectra present the typical boron-doped nanocrystalline diamond line recorded at 1148 cm -1 . Moreover, the change in mechanical parameters of silicon cantilevers over-coated with boron-doped diamond films was investigated with laser vibrometer. The increase of resonance to frequency of over-coated cantilever is attributed to the change in spring constant caused by B-NCD coating. Topography and electrical parameters of boron-doped diamond films were investigated by tapping mode AFM and electrical mode of AFM-Kelvin probe force microscopy (KPFM). The crystallite-grain size was recorded at 153 and 238 nm for boron-doped film and undoped, respectively. Based on the contact potential difference data from the KPFM measurements, the work function of diamond layers was estimated. For the undoped diamond films, average CPD of 650 mV and for borondoped layer 155 mV were achieved. Based on CPD values, the values of work functions were calculated as 4.65 and 5.15 eV for doped and undoped diamond film, respectively. Boron doping increases the carrier density and the conductivity of the material and, consequently, the Fermi level.

Quantitative phase‐mode electrostatic force microscopy on silicon oxide nanostructures

“…Accordingly, V D ranges from – 0.4 to 1 eV for the Co tip which agrees, for example, to the shift of surface potential observed for adsorbed hydrogen on Co films (Duś & Lisowski, 1976); and (iii) in literature, the work function of conductive diamond films used for AFM probe coatings, i.e. Φ cd,bulk , varies from 3.5 to 5.5 eV depending on the doping level and surface treatments (Maier et al ., 2001; Bogdanowicz et al ., 2016) and, in accordance, the potential drop V D for the cd tip ranges from – 0.39 to 1.61 eV that is in agreement to previous studies (Volodin et al ., 2007).…”

Long-Range Electrification of an Air/Electrolyte Interface and Probing Potential of Zero Charge by Conductive Amplitude-Modulated Atomic Force Microscopy

“…42,43 From the linear relation, the PZCs of graphite (work function: 4.6−4.7 eV) 44,45 and graphene (work function: 4.6 eV) 45−47 were, respectively, calculated to be −0.1 to 0.0 V and −0.1 V, which are fairly consistent with the experiments. Because the work function of the sp 3 diamond structure of BDD was reported to be 4.650 to 5.165 eV, 48,49 it is reasonable that the PZC of BDD would be more positive than that of graphite or graphene. Therefore, we concluded that the PZC of BDD in the range of 0.0−0.2 V from our experiment is reliable to verify this unique experimental setup.…”

Low‐Coherence Interferometer with Nanocrystalline Diamond Films with Potential Application to Measure Small Biological Samples

“…The substrates were seeded with mono‐dispersed nanodiamond suspension in ultrasonic bath for 30 min . A special truncated cone‐shaped shim was used during the growth of diamond films . In this study, the molar ratio of CH 4 H 2 mixture was kept at 1% of gas volume at 300 sccm of the total flow rate.…”