  Low-Gain Avalanche Diode (LGAD) sensor is one of candidate sensors for the
tracker at future hadron collider experiments. To use this sensor as a tracking
detector, AC-LGAD sensor is being developed which has both timing and spatial
resolutions. In high luminosity environments, good timing resolution (typically
30 ps) together with $\mathcal{O}$(10) ${\mathrm{\mu}}$m spatial resolution
helps to reduce pileup effect and reconstruct tracks correctly. By optimizing
fabrication parameters, 80 ${\mathrm{\mu}}$m pitch strip and 100
${\mathrm{\mu}}$m pitch pixel sensors are successfully produced. The signal
height (MPV) was 39.26$\pm$0.08 mV and 128.9$\pm$3.3 mV, respectively, for
penetrating $\beta$ particles. The observed 60% of signal reduction of the
strip sensor is explained by a larger inter-electrode capacitance compared with
the pixel sensor. In this paper, we present the performance of fine electrode
pitch AC-LGAD sensors including the pulse height and cross-talk of pixel and
strip type sensors evaluated using a $\beta$-ray source and the detection
efficiency measured in an 800 MeV electron beam.
