Silicon Carbide

Silicon Carbide (SiC) is a wide band-gap semiconductor. Similar to silicon it can be used to make electronic devices which can be employed in several applications. SiC has some unique features, such as wide band-gap, high hardness, chemical inertness, and capability to withstand high temperatures. Its high breakdown electric field, high saturated drift velocity and high thermal conductivity are some of the most important characteristics to understand why SiC have superior electrical properties compared to silicon, and makes it very attractive for power devices especially at high voltages and high frequencies. The gain in reduced device sizes, reduced cooling requirements, and especially in improved energy efficiency for AC/DC conversion are a very important reasons why it is the semiconductor of choice for EV-applications.

Seeded Sublimation

The seeded sublimation method also known as modified Lely method and Physical Vapor Transport (PVT) was introduced by the Russians Tairov and Tsvetkov in 1978. In this method a graphite quasi-closed crucible is placed in low pressure inert gas atmosphere and heated to 2300-2600OC. A single crystal seed is glued to the top of the crucible and SiC source (typically powder) is placed on the bottom of the crucible (Fig. 1). At high temperatures the SiC source sublimes into Si and C bearing species which are transported from the source to the seed crystal to grow a SiC-ingot. The driving force for the growth is created by applying a temperature gradient between the source and the seed.