At Northrop Grumman Mission Systems and Arizona State University, researchers are working on a new project, creating power transistors, but from diamond. They claim diamond power transistors are capable of very high efficiencies. This can significantly shrink the size of power transistors, leading to smaller electrical grid substations, and a potential drop in the cost of cell phone towers.
Manufacturers typically make power transistors from silicon. However, researchers are investigating diamond, because, they claim, it has very high thermal conductivity. Therefore, diamond conducts heat more than 8 to 10 times more efficiently than current materials like silicon. The researchers claim that at their full potential, transistors made of diamond can be smaller than regular power transistors by about 90 percent.
The breakdown field of diamonds is also high. That means, as compared to most other materials, a diamond can withstand large amounts of voltage, before failure. A high breakdown field is advantageous for applications involving high power. Therefore, diamond transistors will be vital to advancing the transition to renewable energy, while electrifying the transportation sector.
Although silicon has been the standard material for making most semiconductor devices, manufacturers also use gallium nitride and silicon carbide for the more advanced modern transistors, mainly for regulating the flow of electrical power. Now, researchers are studying the use of two new transistor materials—boron nitride and diamond,
The researchers are studying diamonds for the main body of the transistor, while they are interested in boron nitride as the electrical contact for the transistor. Similar to diamond, boron nitride, too, has high thermal conductivity and a high breakdown field,
The research team expects to make transistors by combining the two materials. According to them, the two materials complement each other, working even better than they do individually.
Their research will be useful for several applications, such as communication technologies. For instance, satellites typically operate on solar power, requiring transistors to turn power from solar panels into a form usable by the electronics. For launching satellites into space, one of the biggest impediments is its weight and size. Using a smaller power transistor can help to reduce both.
Smaller diamond transistors can improve many other communication technologies as well. This includes towers that cell phones need. Transistors handle the power that these tower systems need to produce radio frequencies for cell phone usage.
According to the researchers, cell phone designers and operators face a huge challenge of keeping the tower systems cool. This is especially true when the tower location is in hot environments, such as in Phoenix.
Cell phone towers typically use power transistors made of silicon, while the newer 5G towers use gallium nitride transistors. With their substantially better heat transfer characteristics, the new diamond transistors can drastically reduce the power needed to cool cell phone tower systems, and also make easier the task of keeping cell tower electronics from overheating.
In addition to communication technology, power conversion applications for electrical systems and the electrical grid will also benefit from the new power transistors made of boron nitride and diamond. Their higher efficiency will significantly reduce the size of electricity grid substations.
