FERROELECTRIC FIELD EFFECT TRANSISTOR WITH THRESHOLD VOLTAGE SWITCHING FOR IMPROVED PERFORMANCE IN ONE STATE AND OUT OF STATE

摘要

Techniques for ferroelectric based field effect transistors (FETs) with threshold voltage (VT) circuitry for improved on-state and off-state performance of an RF switching transistor are disclosed herein. The use of a ferroelectric gate dielectric layer that can switch between two ferroelectric states allows for a higher VT during the transistor off state (VT, hi) and a lower VT during the transistor on state (VT, lo). Accordingly, the resistor in the on state (Ron) of the transistor can be kept low due to the available relatively high gate overdrive (Vg, on -VT, lo), while due to the high VT, hi-VG off value, there still remains one relatively high maximum RF power in the transistor-off state is handled. Therefore, the Ron of an RF switching transistor can be improved without sacrificing the maximum RF power, and / or conversely, the maximum RF power can be improved without sacrificing Ron. A ferroelectric layer (eg comprising Hf _x Zr _y O) may be formed between a transistor gate dielectric layer and a gate electrode to achieve such advantages.