Metallic substrates to enable semiconductors to take the heat

July 20, 2017 //By Christoph Hammerschmidt
An international research team at the Jülich Research Centre (Germany) was the first to develop high-performance transistors on a metallic carrier material. The metal substrate not only reduces the heating of the semiconductor and conducts most of the heat effectively, but also makes the device more stable.

The ever-increasing miniaturization of semiconductor components makes computers and mobile phones smaller, but it has a price: 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. Therefore, new concepts are required. An example are metallic carrier materials for semiconductor components.

"Metals are very good heat conductors," explains 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."


Scheme of the transistor structure on the silver substrate
(C) Forschungszentrum Jülich

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."