  The timing performance of the Timepix4 application-specific integrated
circuit (ASIC) bump-bonded to a $100\;\mu\textrm{m}$ thick n-on-p silicon
sensor is presented. A picosecond pulsed infrared laser was used to generate
electron-hole pairs in the silicon bulk in a repeatable fashion, controlling
the amount, position and time of the stimulated charge signal. The timing
resolution for a single pixel has been measured to $107\;\textrm{ps}$ r.m.s.
for laser-stimulated signals in the silicon sensor bulk. Considering
multi-pixel clusters, the measured timing resolution reached $33\;\textrm{ps}$
r.m.s. exploiting oversampling of the timing information over several pixels.
