Linköping University (LiU) scientists have developed a new molecule to create high-quality indium nitride, a promising material for high-frequency electronics.
With the bandwidth for wireless data transfer reaching its limit, there is a need to increase the same for bringing further frequencies into use. And this is where Indium nitride comes into the picture.
“Since electrons move through indium nitride extremely easily, it is possible to send electrons backwards and forwards through the material at very high speeds, and create signals with extremely high frequencies,” notes team lead and LiU professor Henrik Pedersen.
Indium nitride consists of nitrogen and a metal, indium. It is a semiconductor and can therefore be used in thin films transistors, on which all electronic devices are based.
Thin films are produced using Chemical Vapor Deposition (CVD) method, in which temperatures between 800 C and 1,000 C are used.
The problem is that it is difficult to produce thin films of indium nitride as the material breaks down into its constituents when heated above 600 C.
To remedy this, the LiU team used a low temperature variant of CVD known as Atomic Layer Deposition (ALD).
They also developed a new molecule known as an indium triazenide; no one had worked with such indium triazenides previously.
The team soon realized that the triazenide molecule is an excellent starting material for the manufacture of thin films.
They also discovered that it is possible to achieve epitaxial growth of indium nitride if silicon carbide is used as substrate.
The indium nitride produced in this way is extremely pure, and among the highest quality indium nitride in the world.
Most materials used in electronics must be produced by allowing a thin film to grow on a surface that controls the crystal structure of the electronic material. The process is known as epitaxial growth.
The LiU team also noticed that when they changed the temperature of the coating process, there is not just one, but two temperatures at which the process was stable.
“The indium triazenide breaks down into smaller fragments in the gas phase, and this improves the ALD process,” notes Pedersen.
“We have shown that we can obtain a better final result if we allow the new molecule to break down to a certain extent in the gas phase.”