The power electronics are a decisive component for the control, conversion and switching of electrical energy. Since these semiconductors are often needed in highly demanding applications, they must be stable in the long run, resilient and temperature-resistant. Today, for example, electrical and hybrid vehicles are equipped with such components. Apart from automotive technology, we also find them in entertainment electronics, telecommunication or biomedicine. Modern requirements demand continuous development and improvement of high-voltage and low-loss high-performance semiconductors.
There is a great breadth of semiconductors on the market. The most important features here include: Silicon (Si), silicon carbide (SiC), gallium nitride (GaN) or gallium arsenide (GaAs). Which of these semiconductors are best will be determined by the material properties, the requirements to the device and the costs. Each of these substances has established its own niche.
The number of obstacles to be overcome by use in the increasingly demanding electronics industry, however, increases. Higher performance density, efficiency and reliability are required. The semiconductor industry uses many thermal processes in order to improve diffusion of dopants or oxidise and temper semiconductors. They usually happen in a process gas. "Contaminations" are added to the semiconductor structure under controlled conditions, which causes the performance of the material to change. The diffusion coefficients in semiconductors strongly depends on temperature.
One of the standard methods uses, for example, steam for oxidising silicon surfaces (wet or moist oxidation). It usually happens at temperatures between 900°C and 1100°C. The layer here grows quickly, but the crystal quality is not satisfactory. This reaction can be clearly accelerated by higher temperatures. Dry oxidation (under oxygen and at up to 1200°C) causes optimal crystal growth and much better layer qualities.
Temperature dependence of the diffusion becomes even more important because it not only influences the quality and functional properties of the treated materials, but also shortens the overall process length.
Diffusion is a thermally controlled process. This requires a precise heating system.
SCHUPP® will gladly develop together with you a MolyTec heating system for the controlled and precise heat treatment of semiconductors. We combine high-purity heating elements of molybdenum disilicide (MoSi2) and vacuum-formed insulation parts of non-classified polycrystalline mullite/alumina wool (PCW) according to your requirements. Our heating systems allow process temperatures even up to 1450°C (strongly depending on application and geometry).
The most important influences in the semiconductor industry are temperature and time. Use of MolyTec heating systems permits shortening of the process time by higher process temperatures as compared to wire. Additionally, the system forms a homogeneous temperature distribution and higher performance introduction by MoSi2 heating elements as compared to alternative heating solutions. Fast and uncomplicated installation reduces long maintenance failures. The high-quality components of the heating system lead to a longer service life than that of conventional heating systems (e.g. with wire).