The pressure sensitivity of wrinkled B-doped nanocrystalline diamond membranes

Abstract

Nanocrystalline diamond (NCD) membranes are promising candidates for use as sensitive pressure sensors. NCD membranes are able to withstand harsh conditions and are easily fabricated on glass. In this study the sensitivity of heavily boron doped NCD (B:NCD) pressure sensors is evaluated with respect to different types of supporting glass substrates, doping levels and membrane sizes. Higher pressure sensing sensitivities are obtained for membranes on Corning Eagle 2000 glass, which have a better match in thermal expansion coefficient with diamond compared to those on Schott AF45 glass. In addition, it is shown that larger and more heavily doped membranes are more sensitive. After fabrication of the membranes, the stress in the B:NCD films is released by the emergence of wrinkles. A better match between the thermal expansion coefficient of the NCD layer and the underlying substrate results in less stress and a smaller amount of wrinkles as confirmed by Raman spectroscopy and 3D surface imaging.

Nanocrystalline diamond-glass platform for the development of three-dimensional micro- and nanodevices

“…We suspect that this is caused by tensile stress, which is to be expected since the coefficient of thermal expansion of fused silica is less than that of diamond over the entire range of operating temperatures used during our preliminary experiments [39,55]. Our experiments and previous work [18,56,57] show that NCD films grown on substrates made of any glass listed in Table 1, except fused silica, are compressively stressed, which leads us to suspect that the coefficients of thermal expansion of those types of glass might be greater than that of diamond for significant portions of the temperature ranges used in the relevant growth processes. It is noteworthy that Iliescu et al [28] and Ceyssens and Puers [44] found that compressive stress acting on films, which mask parts of glass substrates during HF etching, is preferable over tensile stress.…”

Can europium atoms form luminescent centres in diamond: A combined theoretical–experimental study

“…The thickness of grown films is determined in situ by observing the interference fringes of a 405 nm laser, and the deposition is stopped after 47 min at a thickness of 150 nm. Samples grown in the same reactor under similar growth conditions 55,56 indicate that the B:NCD films have boron concentrations of approximately 5 × 10 21 cm −3 .…”

Functionalization of boron-doped diamond with a push–pull chromophore via Sonogashira and CuAAC chemistry

“…Characterization performed on samples grown in the same reactor under similar growth conditions indicated that the B:NCD lms have boron concentrations of approximately 5 Â 10 21 cm À3 and a resistivity (U) below 5 mU cm. 41,42…”