  The lack of a bulk second-order nonlinearity (\c{hi}(2)) in silicon nitride
(Si3N4) keeps this low-loss, CMOS-compatible platform from key active functions
such as Pockels electro-optic (EO) modulation and efficient second harmonic
generation (SHG). We demonstrate a successful induction of \c{hi}(2) in Si3N4
through electrical poling with an externally-applied field to align the Si-N
bonds. This alignment breaks the centrosymmetry of Si3N4, and enables the bulk
\c{hi}(2). The sample is heated to over 500{\deg}C to facilitate the poling.
The comparison between the EO responses of poled and non-poled Si3N4, measured
using a Si3N4 micro-ring modulator, shows at least a 25X enhancement in the r33
EO component. The maximum \c{hi}(2) we obtain through poling is 0.24pm/V. We
observe a remarkable improvement in the speed of the measured EO responses from
3GHz to 15GHz (3dB bandwidth) after the poling, which confirms the \c{hi}(2)
nature of the EO response induced by poling. This work paves the way for
high-speed active functions on the Si3N4 platform.
