Single-device-well MOSFET's

A novel MOSFET structure based on merging a surface enhancement-type device and a buried depletion-type device in a Single Device Well (SDW) is described. The SDW MOSFET structure utilizes the inherent two-dimensional geometry of a MOSFET device well to obtain two devices perpendicular to each other, having the same gate, thereby utilizing the hitherto nonutilized volume of the well. The two perpendicular currents of the devices in the merged structure are analyzed. An analytical model is developed and circuit CAD simulations are performed. A test chip is fabricated and the structure performance is evaluated. Some circuit examples are given.