  We derive expressions for the time resolution of silicon detectors, using the
Landau theory and a PAI model for describing the charge deposit of high energy
particles. First we use the centroid time of the induced signal and derive
analytic expressions for the three components contributing to the time
resolution, namely charge deposit fluctuations, noise and fluctuations of the
signal shape due to weighting field variations. Then we derive expressions for
the time resolution using leading edge discrimination of the signal for various
electronics shaping times. Time resolution of silicon detectors with internal
gain is discussed as well.
