A new non-volatile memory technology for embedded memory applications is described. The technology uses one
cantilever per cell with two stable states to store information. The two stable states are either stuck down to a landing
electrode or not. Because the cantilever and landing electrodes are conducting, each cantilever can be read easily by
measuring the contact resistance between the two. The cantilever stays in the 'on' state due to short range attractive
forces at the contact including metal-to-metal bonding and Van der Waals forces. Using standard CMOS processing
equipment and materials the cantilevers are designed to switch at the native voltages found in micro-controllers, making
this technology an attractive alternative to other forms of embedded non-volatile memory as it reduces the memory block
area by eliminating the requirement for charge pumps. With scaling of the cantilever geometries, the switching speed
drops to below 100ns making it very much faster to program and erase than FLASH and SONOS devices. The high
activation energies associated with adhesion ensure that the technology is reliable over a wide temperature range. In
this paper we discuss how the cantilevers are encapsulated in a wafer scale CMOS process and how the resulting microcavities
are qualified. We will discuss how the contact adhesion forces are modeled to give controllable erasure of the
cantilever into the 'off' state.
We report the control of flow direction of a dilute salt solution in a microchannel by external voltage control of an ac electrokinetic micropump. Reversal of the flow velocity is achieved when a voltage of 2.0 V is applied to the drive electrodes and we show that the reverse velocity increases non-linearly with voltage above this value. Velocities of more than 250 um/s at a distance of 75 μm above the electrode surfaces have been measured, which is much greater than in the forward direction. A possible mechanism based on faradaic charge injection is proposed to explain the onset and propagation of reverse flow. We have also shown how multi-directional flow control can be utilized to promote mixing of fluids in a microchannel, and suggest a biochip application which can benefit from this new pumping technology.