Bottom source NMOS triggered zener clamp for configuring an ultra-low voltage transient voltage suppressor (TVS)

摘要

A low voltage transient voltage suppressing (TVS) device supported on a semiconductor substrate supporting an epitaxial layer thereon. The TVS device further includes a bottom-source metal oxide semiconductor field effect transistor (BS-MOSFET) comprises a trench gate surrounded by a drain region encompassed in a body region disposed near a top surface of the semiconductor substrate wherein the drain region interfaces with the body region constituting a junction diode and the drain region encompassed in the body region on top of the epitaxial layer constituting a bipolar transistor with a top electrode disposed on the top surface of the semiconductor functioning as a drain/collector terminal and a bottom electrode disposed on a bottom surface of the semiconductor substrate functioning as a source/emitter electrode. The body regions further comprises a surface body contact region electrically connected to a body-to-source short-connection thus connecting the body region to the bottom electrode functioning as the source/emitter terminal. The gate may be shorted to the drain for configuring the BS-MOSFET transistor into a two terminal device with a gate-to-source voltage equal to a drain-to-source voltage. The drain/collector/cathode terminal disposed on top of the trench gate turns on the BS-MOSFET upon application of a threshold voltage of the BS-MOSFET thus triggering the bipolar transistor for clamping and suppressing a transient voltage substantially near a threshold voltage of the BS-MOSFET.