A field‐effect transistor in which the ferroelectric lithium niobate (LiNbO3) replaces the oxide in a conventional metal‐oxide‐semiconductor transistor has been fabricated. The channel conductance of this device has been shown to be strongly affected by the application of voltage pulses between the gate of the device and the substrate. A reduction of channel current of nearly 140 &mgr;A was observed after the application of a voltage pulse of −30 V and partially restored witha+10‐V pulse. This behavior was found to be consistent with the influence of the polarization charge of the LiNbO3layer on the carriers in the channel. This is the first observation of such behavior in a metal‐ferroelectric‐semiconductor field‐effect transistor without the growth of a buffer layer between the semiconductor and ferroelectric to prevent charge injection.