SiC Amplifying Gate Thyristor Evaluation – AGaThE

Power electronics is a key technology to meet the steadily growing demands on civil and defence applications, in particular concerning an efficient handling of electric energy resources for both power supply networks and autonomous mobile platforms. Owing to its outstanding physical properties, silicon carbide (SiC) is the semiconductor material of choice for improved high power diodes and thyristors meeting the performance requirements of future high power converter and pulsed power technologies. The amplifying gate is state of the art in large area, silicon based phase control (PCT) and light trigged thyristors (LTT). As a result of the continuous progresses in SiC material quality and wafer diameter the amplifying gate structure is about to become interesting for SiC thyristors.
Goal of the research project is the basic development and study of amplifying gate thyristors (AGT) based on SiC. The type of thyristor we suggest to realize and investigate consists of a small auxiliary thyristor integrated in a large principal thyristor. The former permits to inject a current in the gate of the latter, permitting its switch-on. This design results in smaller gate current pulses and homogeneous turn-on of the device. The structure of the gate of the auxiliary thyristor and the gate of the main thyristor determine the turn-on delay of the thyristor. Thus, the aim is to simulate the switching behaviour of different gate-anode structures and to compare the developed simulation models to the electrical characteristics of AGTs which will be thoroughly designed and realized within the project. In addition, we intend to study the current spreading during turn-on and investigate the concept of emitter short cuts as applied to AGTs. All these results will be used to reveal characteristic differences of silicon and SiC thyristors concerning the current spreading during turn-on and finally to dimension high voltage (> 10 kV) large area SiC AGTs.