The increasing density of these circuits makes it difficult to dissipate the heat. This not only has a detrimental effect on the function of the components, but also on their service life. Efficient heat dissipation is therefore essential for the further development of circuits, especially when high computing speeds and performance are required.
“Metals are very good heat conductors,” said Hilde Hardtdegen from the Peter Grünberg Institute of the Jülich research centre in Germany who headed the research team. “However, so far, they have not been considered as carrier materials. Different chemical and physical properties and above all differences in the crystal lattice made it impossible to apply monocrystalline semiconductor layers to metallic substrates using conventional methods.”
Jülich scientists have now succeeded for the first time, together with colleagues from Slovakia, the Czech Republic and Australia, to build such semiconductors on metallic carrier substrates.
How much better metalic materials carry away the heat depends on the temperature range. High-performance transistors heat up to several hundred degrees Celsius during operation. In this temperature span, the silver substrate used by the research team exhibit more than eight times the thermal conductivity of conventional Sapphire substrates. This reduces the effect of heating up the semiconductor structures by up to 70 percent.”
The possible applications for such a metallic substrate material are numerous: high-performance electronics for mobile radio networks, components for the automotive and aircraft industry, even everyday devices such as mobile phones or tablets – wherever heat development can adversely affect the function of devices.
But before such semiconductors can be implemented in an industrial scale the laborarory processes need to be adapted to the requirements of mass production, as well as to the respective technical specifications for various end products, says Hardtdegen. “Above all, stability and repeatability need to be optimized.” This will take some five to seven years, at best, the researcher adds.
Original publication: M. Mikulics, P. Kordos, A. Fox, M. Kocan, H. Lüth, Z. Sofer, H. Hardtdegen, Efficient heat dissipation in AlGaN / GaN heterostructure grown on silver substrate, Appl. Mater Today vol. 7 pp. 134-137, 2017 (see https://www.sciencedirect.com/science/article/pii/S235294071730029X)