Big Opportunity From Tiny Machines
Back in 1959, Nobel-winning physicist Richard Feynman delivered a now-famous talk titled “There’s Plenty of Room at the Bottom,” in which he envisioned the potential applications of tiny machines. Today, one of the most important innovations leading to the current generation of smartphones and tablets is known as MEMS…
Shorthand for “micro-electromechanical machines,” MEMS are the tiny machines embedded in these products, which provide information regarding position and movement. When your mobile device changes how its screen displays when you rotate it, it is an MEMS device that tells it which way it is oriented. Like most of the electronic innards of a modern computer, MEMS are usually manufactured out of silicon.
With funding from the National Science Foundation, University of Wisconsin-Madison researchers have advanced MEMS technology by integrating new piezoelectric materials on silicon. Piezoelectric materials store an electrical charge when under mechanical force, or expand and contract under the influence of electrical fields. If you’ve used a lighter or propane barbecue that has an electrical igniter, you have seen piezoelectricity at work. Children’s shoes that light up when they step also use piezoelectricity to generate a small electrical current.
The University of Wisconsin-Madison researchers studied a piezoelectric material called lead magnesium niobate-lead titanate, or PMN-PT for short. PMN-PT is a very high-performance piezoelectric crystal that is used, among other things, to deliver waves of ultrasound into the human body to produce 3-D images.
Due to its high level of piezoelectric performance, which includes the ability to work using lower amounts of electrical consumption, PMN-PT would be very useful in MEMS devices. It could be used as part of a machine to act as a tiny switch in optical communications devices, or it could enable a new generation of electronic filters for radio-frequency communications in mobile devices. As a sensor, it could increase sensitivity over currently available MEMS technology.
The problem with PMN-PT is that current commercial manufacturing methods that require the material to be cut, ground and polished from bulk materials. These imprecise “top down” manufacturing techniques mean that it cannot be used for many potential applications. It cannot be handled with enough small-scale precision to make it suitable for use in MEMS devices.
Here is where the new research comes in. The University of Wisconsin-Madison engineers figured out a way to apply fabrication techniques common in the semiconductor industry to PMN-PT. By carefully adding thin layers of a special electrode material on top of a layer of silicon, they were able to add a layer of PMN-PT that performs every bit as well as bulk crystals. The end result of applying atomic-level control to PMN-PT could be more-efficient MEMS circuits, including devices that can convert vibration into electricity for small devices.
Needless to say, we’re on the lookout for the best new technologies that represent investment opportunities. We expect to find exciting candidates in the MEMS field and elsewhere.
Regards,
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