Translated abstract:
The topic of this work is the capacitive stimulation of adherent nerve cells by using semiconductor chips. The capacitance of the chips is enhanced by using the materials TiO2 and HfO2, which feature a high dielectric constant. Due to the low leakage current of the used electrolyte/oxide/semiconductor configuration, capacitance measurements more detailed as possible in MOS system, can be carried out. To interpret the results, the band structure is numerically simulated. The novel TiO2 stimulation chips exhibit a five-fold capacitance increase as compared to formerly used SiO2 chips. Using them, two fundamental stimulation mechanisms could be discriminated: For falling voltage ramps of low duration applied to the chip, ion channels were opened. At shorter ramp durations, electroporation sets in additionally. For rising voltage ramps, only electroporation can be induced.