Vertical silicon nano-pillar for non-volatile memory

NanoElectroMechanical (NEM) switches have been proposed for non-volatile memory applications, but low device density remains a key challenge for horizontal switches. This paper presents a resistive, vertically oriented NanoElectroMechanical (NEM) nano-pillar cantilever switch made of mono-crystaline silicon, with a cell size of 8F². Using a top-down CMOS-compatible process requiring two lithography masks, nano-pillar switches with a height of 500nm, tip thickness of 35nm, and 25nm air gap are fabricated. Device switching is performed using electrostatic actuation, while non-volatile memory function is achieved by maintaining switch contact with van der Waals forces after pull-in even when the actuating voltage is removed. Switching and non-volatile memory capabilities are demonstrated, with pull-in voltage V_pi = 17V and release voltage V_release = -25V. With low-cost fabrication process and high device density, the nano-pillar device is a promising candidate for non-volatile memory applications.