The most obvious change in transistor technology over the last 75 years has been how much we can make. As these charts show, reducing the size of devices has been a tremendous effort, and very successful. But size isn't the only feature that engineers have been improving.

In 1947, there was only one transistor. According to TechInsight, the semiconductor industry is on track to produce nearly two billion trillion (1,021) devices this year. That's more transistors than have been manufactured cumulatively in all years up to 2017. Behind this almost unimaginable number is a steady decline in transistor prices as engineers have learned to integrate more and more transistors into the same silicon area.

Shrinking transistors in the two dimensions of the silicon plane has been a huge success: since 1971, the density of transistors in logic circuits has increased by more than 600,000 times. Shrinking transistor sizes requires the use of shorter wavelengths of light, such as extreme ultraviolet light, and other lithography techniques that can reduce the space between transistor gates and between metal interconnects. Looking ahead, it is important that it is the third dimension, where transistors will be built in another dimension. This trend has been around for more than a decade in flash memory, but is still in the future in logic.

Perhaps the crowning achievement of all these efforts is the ability to integrate millions or even billions of transistors into some of the most complex systems on the planet: the CPU. let's look at the evolution of the transistor in the diagram below.

Here are some of the advances in the industry

In addition to making them small and numerous, engineers have worked to improve other qualities of devices. The following is a small sampling of how transistors have evolved over the past 75 years.

Illinois researchers have developed circuits that dissolve in the body using a combination of ultra-thin silicon films, magnesium conductors and magnesium oxide insulators. Five minutes in water was enough to turn the first generation into a paste. But recently researchers used a more durable version to create temporary pacemakers that release an anti-inflammatory drug when they wear off.

The first transistors were made for radio frequencies, but there are now devices that operate at about a billion times those frequencies. Engineers in Korea and Japan report inventing an indium gallium arsenide high electron mobility transistor (HEMT) with frequencies up to 738 GHz. engineers at Northrop Grumman, in their quest for raw speed, built a HEMT that exceeded 1 terahertz.

Today's (and yesterday's) transistors depend on the semiconductor properties of block (3D) materials. Tomorrow's devices may rely on two-dimensional semiconductors, such as molybdenum disulfide and tungsten disulfide. These transistors may be built into the interconnect layer above the processor silicon, the researchers say. So 2D semiconductors could help produce 3D processors.

The world isn't flat, and neither is the place where transistors need to run. Korean engineers recently used indium gallium arsenide to create high-performance logic transistors on plastic that are barely affected when bent to a radius of just 4 millimeters. Engineers in Illinois and England have created microcontrollers that are both economical and bendable.

When you need to hide your computing in plain sight, use transparent transistors. Researchers in Fuzhou, China, recently created a transparent flash memory analog using organic semiconductor thin-film transistors. Researchers in Japan and Malaysia have produced transparent diamond devices that can withstand voltages of more than 1,000 volts.

NAND flash memory cells can store multiple bits in a single device. Researchers at Kioxia Corp. built a modified NAND flash cell and immersed it in liquid nitrogen at 77 Kelvin. An ultracold transistor can store up to 7 bits of data, or 128 different values.

In 2018, engineers in Canada used an algorithm to generate all possible unique functional basic circuits that could be made using just two metal oxide field-effect transistors. The total number of circuits reached a staggering 582. extending the range to three transistors yielded 56,280 circuits, including several amplifiers previously unknown to engineers.

Some transistors can withstand extraordinary punishment. 200 transistorized silicon carbide ICs were built at NASA's Glenn Research Center and run for 60 days in a chamber that simulated the surface environment of Venus - 460 °C, 9.3 MPa of pressure from crushing planetary probes, and a hellishly corrosive planetary atmosphere.