A team headed by researchers at University of Wisconsin-Madison, has come up with a way of embedding fast transistors and integrating wireless technology into highly flexible plastic sheets. The technology should apparently be easy to introduce and result in cheap manufacturing costs, allowing it potentially be used in a variety of medical and health related devices.
The transistors operate at 38 GHz and further testing and refinement can get that up even higher, allowing for powerful computing capabilities right inside the flexible film. The material could integrate body sensors and measure different parameters while conforming to the natural shape of the body and being comfortable to wear.
Here are some details about the production process according to UW-Madison:
Using low-temperature processes, Ma, Seo and their colleagues patterned the circuitry on their flexible transistor — single-crystalline silicon ultimately placed on a polyethylene terephthalate (more commonly known as PET) substrate — drawing on a simple, low-cost process called nanoimprint lithography.
In a method called selective doping, researchers introduce impurities into materials in precise locations to enhance their properties — in this case, electrical conductivity. But sometimes the dopant merges into areas of the material it shouldn’t, causing what is known as the short channel effect. However, the UW–Madison researchers took an unconventional approach: They blanketed their single crystalline silicon with a dopant, rather than selectively doping it.
Then, they added a light-sensitive material, or photoresist layer, and used a technique called electron-beam lithography — which uses a focused beam of electrons to create shapes as narrow as 10 nanometers wide — on the photoresist to create a reusable mold of the nanoscale patterns they desired. They applied the mold to an ultrathin, very flexible silicon membrane to create a photoresist pattern. Then they finished with a dry-etching process — essentially, a nanoscale knife — that cut precise, nanometer-scale trenches in the silicon following the patterns in the mold, and added wide gates, which function as switches, atop the trenches.
Study in Scientific Reports: Fast Flexible Transistors with a Nanotrench Structure…
(hat tip: Engadget))