Researchers from MIT have made an unexpected discovery that allows for the 3D printing of active electronics, including transistors and components used for controlling electrical signals, without relying on semiconductors or specialized fabrication technologies.
This development far exceeds current 3D printing capabilities. If this technique is refined, it could herald a new era in prototyping, experimentation, and even DIY projects for enthusiasts at home.
Using 3D printing, various materials such as thermoplastic filaments, resin, ceramics, and metals can be deposited in successive thin layers to create three-dimensional objects. This means a wide range of items can be produced, from action figures to jewelry, furniture, and even buildings.
So, why haven’t we been able to 3D print functional electronics? The primary hurdle is that semiconductors, typically made from pure silicon and sliced into thin wafers to create chips for electronic devices, are quite fragile. Their performance can be compromised by dust, airborne particles, microbes, as well as fluctuations in temperature and humidity. Consequently, these components are meticulously handled in cleanrooms, where air quality and other variables are meticulously monitored to ensure that the manufactured chips operate flawlessly.
Moreover, the design of modern chips is highly intricate, featuring millions or even billions of transistors densely packed into small processors utilizing nanometer-level processing methods. This precision far surpasses the capabilities of standard 3D printing technology available today.
For context, IBM’s Gekko chip that powered the Nintendo GameCube in 2001 contained 21 million transistors. In comparison, the Apple A12 Bionic chip featured in the 2018 iPhone XS included 6.9 billion transistors and was produced using a 7-nanometer process technology.
It’s important to note that the goal of the MIT researchers was not to 3D print modern devices. Surprisingly, their focus was not even on semiconductors when they made this discovery.
During their work, the researchers were creating magnetic coils through a technique known as extrusion printing for a different project. It was during this process that they noticed an intriguing phenomenon: the polymer filament they were using, which was infused with copper nanoparticles, displayed a significant increase in resistance when electric current was applied. Interestingly, once the current was cut off, the resistance of the material returned to its normal levels.
This is essentially the characteristic we observe in semiconductors such as silicon. It explains our reliance on them for crafting transistors that toggle on and off to create logic gates in processors.
“We recognized that this could elevate 3D printing technology,” remarked Luis Fernando Velásquez-García, principal research scientist at MIT’s Microsystems Technology Laboratories. “It provides a distinct approach to infuse a degree of ‘intelligence’ into an electronic device.”
The research team showcased fully 3D-printed resettable fuses and transistors utilizing this cost-effective material. These components, although simple, are vital for electronic devices that often depend on challenging-to-manage semiconductors.
Measuring just a few hundred microns, these transistors may not compete in size or performance with those found in an iPhone processor. Nevertheless, they boast durability and can serve various straightforward functions. This includes basic applications like a switch for operating a motor, as well as components for integrated circuits.
“The truth is, numerous engineering scenarios do not necessitate the top-tier chips,” shared Fernando Velásquez-García. “Ultimately, what matters is if your device can perform its intended function. This technology addresses such a requirement effectively.”
Utilizing a biodegradable material and eliminating the need for cleanrooms, this approach to creating basic electronics presents possibilities in areas where advanced manufacturing is challenging, such as remote research facilities and aboard spacecraft.
Now that’s what I would refer to as a serendipitous discovery. A research paper has been published in the journal Virtual and Physical Prototyping.
Source: MIT News