Electronic devices that are dense with components can overheat and fail leading to poor performances and system failures. This is especially pertinent when heat from hot components is spread laterally to its surrounding devices causing a cascading effect.
Now, scientists at Nanyang Technological University’s School of Electrical and Electronic Engineering (EEE), Silicon Technologies, Centre of Excellence (Si-COE) have developed a way to ‘grow’ thick boron nitride (BN) thin films that discharge most of their heat vertically rather than laterally.
These vertically-oriented nanocrystalline boron nitride thin films could be used to minimise the risk of electronic devices becoming too hot internally.
The researchers used high power impulse magnetron sputtering for the controlled growth of these films.
Since boron nitride is electrically insulative, a lanthanum hexaboride target was used instead and reactively sputtered in nitrogen gas to grow the films.
The surface roughness of the films was below 1 nm RMS, which makes it usable for electronic devices, and the low lanthanum content in the film does not change the material’s insulative properties.
Unlike other high thermally conductive dielectric materials, such as diamond and cubic boron nitride, the EEE films can be deposited at room temperature. The scientists also created films with thicknesses beyond 1.5 micrometres without any film dislocation at the interface between the silicon substrate and the film.
The EEE films have considerably high thermal conductivity, comparable to nanocrystalline graphite grown at 300 degrees Celsius, and four times higher than that of amorphous silicon dioxide, which is used in high-power electronics.
“Our films’ favourable thermal conductivity is useful for heat dissipation from active regions of electronic devices if they are used to replace silicon dioxide as the gate dielectrics,” said Professor Edwin Teo Hang Tong from EEE.
“They could be an alternative to silicon dioxide in high- power electronics where the dielectric layer is always the thermal bottleneck due to its poor thermal conductivity,” he said.
By Professor Edwin Teo Hang Tong
Click here to find out more.
Published on: 29 September-2017