The efficacy of neural electrode stimulation and
recording hinges significantly on the choice of a neural electrode interface
material. Transition metal carbides (TMCs), particularly titanium carbide
(TiC), have demonstrated exceptional chemical stability and high electrical
conductivity. Yet, the fabrication of TiC thin films and their potential
application as neural electrode interfaces remains relatively unexplored.
Herein, we present a systematic examination of TiC thin films synthesized
through nonreactive radio frequency (RF) magnetron sputtering. TiC films were
optimized toward high areal capacitance, low impedance, and stable
electrochemical cyclability. We varied the RF power and deposition pressure to
pinpoint the optimal properties, focusing on the deposition rate, surface
roughness, crystallinity, and elemental composition to achieve high areal
capacitance and low impedance. The best-performing TiC film showed an areal
capacitance of 475 μF/cm2 with a capacitance retention of 93% after
5000 cycles. In addition, the electrochemical performance of the optimum film
under varying scanning rates demonstrated a stable electrochemical performance
even under dynamic and fast-changing stimulation conditions. Furthermore, the
in vitro cell culture for 3 weeks revealed excellent biocompatibility,
promoting cell growth compared with a control substrate. This work presents a
novel contribution, highlighting the potential of sputtered TiC thin films as
robust neural electrode interface materials.