Engineering low resistance contacts on p-type hydrogenated diamond surfaces

Boron‐Doped Nanocrystalline Diamond Microelectrode Arrays Monitor Cardiac Action Potentials

“…The surface structure of the all‐diamond chips generated by the final plasma treatment is proposed to improve cell recordings in two ways. Firstly, the cells can better adhere to the topography of the surface, as has been shown previously for adhesion on rough materials 25–33. Secondly, the increased surface area of the electrode lowers the impedance, allowing better AP detection.…”

“…Although the BNCD is expected to display near metallic behavior in its bulk at 10 21 cm −3 doping,27 we measure its resistance as 30 Ω m and the diamond likely supports a Schottky barrier at the Ag–diamond interface 28. The more reactive Ti–diamond interface overcomes this problem, likely by forming a carbide interface, leading to a more ohmic‐like contact 29. The TiSi 2 film had a resistance of 1.4 × 10 −6 Ω m. The bandwidth of all chips lies within the range suitable for detecting cell APs (150–1100 Hz for the sodium and potassium components).…”

Direct determination of the barrier height of Au ohmic-contact on a hydrogen-terminated diamond (001) surface

“…Although it was not specifically stated that the specimen surface was H-terminated, a similar analysis of Au ohmic-contact on an as-grown polycrystalline diamond gave a barrier height of ~0.55 eV based on thermal field emission theory [17]. In these studies, specific contact resistances of Au ohmic-contacts were reported to be ~0.1 [17], ~0.04 [15], and ~0.5 [16] cm 2 at RT.…”

“…4 values were obtained from the analyses of measured specific contact resistance R C by the thermionic emission theory [15,16]. Characteristics (at RT) of Au ohmic-contact on H-terminated diamond so far published in literature (to the authors' knowledge) are summarized in Table I.…”

“…Looi et al [15,26] assumed the depth to be ~20 nm and an acceptor concentration of ~110 17 /cm 3 and used thermionic emission theory in the analysis. Teraji et al assumed the same acceptor concentration of ~1.510 15 /cm 3 of that in the boron-doped substrate and used thermionic emission theory [16].…”