Untersuchungen zu Siliziumkarbid-Leistungshalbleiterschaltern für Wechselrichter mit erhöhten Anforderungen (English shop)

Preview

Table of Contents, Datei (54 KB)
Extract, Datei (220 KB)

Advances in semiconductor technology have led over the past decades to mature power semiconductor switches based on silicon (Si). In order to extend the physical limits of these devices in the future, the use of a semiconductor material with a wider band gap is a promising approach. This includes the material silicon carbide (SiC), which holds the prospect of more robust and more efficient power semiconductors and thus more compact systems.

The thesis first presents selected applications with increased requirements (automotive, photovoltaics) in which an extension of the temperature range or a higher efficiency by means of SiC semiconductors would be advantageous. The current Si power semiconductor devices, their packaging and interconnection technology, loss mechanisms and cooling represent the state of the art for this purpose and thus the reference for comparison with new semiconductors.

The differences between SiC and Si technology are explained on the basis of the material properties and the semiconductor structures based on them. The dynamic and static properties were investigated experimentally on available SiC samples and compared with the Si reference, taking into account identical operating conditions and identical chip areas and chip utilisations. On the basis of the variation of the investigation parameters, the dependencies of the loss components are further shown, from which favourable application conditions can be derived. The results reflect a comparison between the technologies of the investigated Si and SiC samples, whereby the approach pursued here can also be transferred to other prototypes.

The potential for applications is demonstrated by loss estimations for a three-phase inverter with junction temperatures up to 200 °C and switching frequencies up to 30 kHz. The verification of the results and the assessment of the applicability of SiC power semiconductors were carried out on a SiC JFET and a SiC MOSFET test inverter.