On the breakdown physics of trench-gate drain extended NMOS

In this work, two drain extended NMOS (DeNMOS) devices, one with only planar gate and another with both planar gate and gate in a trench under the gate-drain overlap region (called trench-gate DeNMOS) are investigated. The latter device shows improved ON-state performance due to greater spacecharge control with addition of trench gate. The OFF-state breakdown physics is also compared with conventional DeNMOS device. Due to greater field spreading in the trench-gate device under OFF-state conditions, a distinct base-push effect is not observed, unlike conventional device. The oxide reliability in trench-gate device improves with an additional offset in the drift region. Therefore, the trench-gate DeNMOS can be used as an alternative to improve input/output (I/O) device performance and reliability in advanced system-on-chip (SoC) applications.