Questions by kids: do semiconductors really come from sand

Two Boise State students hold up a silicon wafer in the lab. Photo credit Priscilla Grover

Learning is all about asking questions, and children ask the best questions. Boise State is home to more than 1,400 faculty members and researchers who are eager to answer these amazing questions.

Today, Foundation Board Endowed Professor of Microelectronics Education and Research in the Department of Electrical and Computer Engineering, and Director of the Microelectronics Education and Research Center Kurtis Cantley answers a child's question: "Do semiconductors really come from sand?

At Boise State, Cantley teaches electrical engineering courses and conducts research with students and faculty on the general capabilities and applications of artificial neural networks that mimic biology.

As the Microelectronics Education and Research Center (MERC) director, Cantley says

"My goal with MERC is to make Boise State a world renowned microelectronics University," Cantley said. "It's already one of our strengths and I just want to continue making sure that we're key players in developing the next-generation semiconductor workforce, and that we give students opportunities to learn all about a really cool field that uses the most advanced technology we've ever created on Earth."

First, what is a semiconductor?

A researcher carefully holds a pure silicon wafer. Photo credit Priscilla Grover

You have metals that usually conduct electricity very well, Cantley explains, and you have insulators that usually do not conduct electricity well.

In the middle, you have certain materials that conduct electricity, but not quite as well as a metal, and then they're not also perfectly insulating: that is a semiconductor. The most common one is silicon.

Semiconductors are useful because you can adjust their properties by doing what we call 'doping', or adding other elements to the material - like phosphorus or boron - to change the electrical properties and make them better suited for specific kinds of electronics.

Are semiconductors made of sand?

For silicon semiconductors, yes! You take sand - which is mostly silicon dioxide - and then you purify that and get the silicon out. Then we melt the silicon down and remove impurities so it is only the silicon atoms. Next, you grow a big cylinder (that we call an ingot) from a little seed crystal of pure silicon.

In the semiconductor industry, we use a mechanized process where there's this big molten amount of silicon, and then you dip that seed crystal of silicon into it, and as you pull it out, you get this huge cylinder of very pure crystalline silicon. You can dope it at that time, too, if you add just the right levels of other elements.

This whole process is called the Czochralski method after the Polish scientist, Jan Czolchralski, who invented the technique in 1915.

Finally, you slice the large ingot - like a big loaf of bread- into wafers. At Boise State, we use wafers that are usually cut from an ingot that is 100 millimeters in diameter (about four inches). At industry sites that conduct really really high-end processing, like Micron and Intel, they use large, 300 mm (about 12 inch) wafers.

• Watch: How Are Microchips Made? The Most Advanced Manufacturing Process on Earth

A researcher works on a silicon wafer in the Idaho Microfabrication Laboratory clean room. A clean room is very important when handling semiconductors, because tiny particles of dust in the air can land on the wafers and ruin them. Photo credit Priscilla Grover

Why do semiconductors matter?

Pretty much any electronic device will have some semiconductors in it, Cantley explains. Phones, laptops, smart devices; you name it. Because of this, semiconductor technology, research and development is critical to the economy, and is responsible for hundreds of thousands of jobs in the US.

Industry in Silicon Valley in California - such as the company Intel - led the creation of much of this technology in the 1970s. It's a technology that was invented here in the United States, but much of it was outsourced. Since then, countries like Taiwan, South Korea, and Japan have become leaders in semiconductor development and fabrication.

Right now, we're in an interesting time period in which we're trying to bring more of that supply chain, technology and manufacturing back into the United States.

That's a big part of what we are doing here at Boise State through education, research, and national and international collaborations, through programs like Upwards for the Future with our university peers and industry colleagues in the US and Japan.

Learn more!

For Kids:

• Microchip makers
• Semiconductors - Featuring Owyhee Produce
• Semiconductors - Featuring Rekluse

For Adults:

• Chip War: The Fight for the World's Most Critical Technology
• Semiconductor for All: Introductory Course

Share This

• Share on Facebook
• Share on X
• Share on LinkedIn
• Share through Email