Silicon photonic modulators are a key component for electro-optic transmitter within data centers. Electro-refractive modulators relying on free carrier plasma dispersion in Mach-Zehnder interferometer have become the most popular solution. Accumulation–based capacitive modulators are an efficient approach, which can reduce the modulation power consumption. In this work we study the behavior of capacitive modulators with polycrystalline silicon to form the capacitance. The modulators are made within the standard fabrication flow with only few add-ons. In this work we show that furnace annealing conditions and excimer laser annealing conditions during the polycrystalline silicon formation enhance the modulator bandwidths.