MIT creates tiny 22nm transistor without silicon


The term “Silicon Valley” is extremely familiar to techies and non-techies alike—it’s a place in the San Francisco Bay Area where big tech firms such as Apple, Hewlett-Packard, Adobe, Intel, Oracle, Western Digital, nVIDIA, and SanDisk are located, and also home to some of the most visited websites in the world, such as Google, Facebook, and Yahoo!. Not surprisingly, Silicon Valley is also the birthplace of the microprocessor, the microcomputer, and of course, the silicon-based integrated circuit, all mainstays in most of the devices we use today.

However, on the other end of the United States is one of the most important research universities in the whole world, the Massachusetts Institute of Technology (MIT), and they have taken the silicon out of the tech world with a new 22 nm transistor, something that may seem unthinkable, as the one element that is often tied to tech products happens to be silicon. Researchers at MIT’s Microsystems Technology Lab (MTL) have created the smallest transistor fashioned from indium gallium arsenide, a material that is being positioned as an eventual successor to silicon.

The science that lead to indium gallium arsenide (InGaAs) was fashioned through normal semiconductor processes, but instead of using silicon, scientists went with evaporated indium, gallium, and arsenic atoms. They then allowed the materials to react, forming a very thin crystal of InGaAs that will become the transistor’s channel in the thin, lighter line at the tip of the inverted V in the picture. The element molybdenum is then deposited at the source and drain, oxide is deposited at the gate, the inverted V, and a tiny, exotic transistor is formed.

Why take silicon out of the tech world? One thing many people might not know is that the world’s supply of silicon, the basic building block of every computer chip, is dwindling quickly—estimates put the remaining supply of the world’s silicon at around 10 to 20 years. As components in computers continue to shrink in size, silicon won’t function as a semiconductor anymore, and alternatives will have to be sought out to replace it. In the picture below are some of the proposed alternatives to silicon and their applications.

MIT’s InGaAs will take anywhere from five to ten more years before it can hit the market. Another problem with these silicon alternatives is that they’re competing to replace some of the most sophisticated and advanced technology in the world. It is said that billions, perhaps trillions of dollars were sunk into complementary metal oxide semiconductor (CMOS) research and development, and it is suggested that the fate of these silicon alternatives lies in the hands of Intel, which has the time and resources to put into their research and development. It is also currently unknown how much further silicon alternatives will scale from silicon. If Moore’s Law, which dictates that the number of transistors on integrated circuits doubles every two years, holds to be true, we might have a successor to the so-called Silicon Valley—how does InGaAs Valley sound?