We propose and demonstrate a hybrid transistor based on a thin film of sulfonated polyaniline (SPAN) deposited on n-Si, forming a Schottky barrier. Two Al contacts deposited onto the SPAN act as source and control terminals. We find that the device operation involves two regimes of charge carrier transport as a function of the voltage applied to the drain: (i) a space-charge limited (SCL) regime at low voltages created by the electrons that diffuse from the Al electrodes and accumulate near the SPAN/Si interface and (ii) a thermionic regime at higher voltage where transport is limited by charge carrier injection over the Schottky barrier at the SPAN/Si interface. Due to the electric field enhancement near the edge of the source terminal, the voltage in the control terminal increases the Schottky effect near the SPAN/silicon interface in this regime. This mechanism permits the modulation of current reaching the drain by the voltage applied to control terminal. From the current-voltage characteristics of the transistor in the SCL regime, we estimate the minority carrier mobility in SPAN. We constructed devices gaps of 22 and 45 μm between source and control terminals and a SPAN film thickness between 150 and 250 nm, achieving source current gain up to 2 × 103.