The IHT and transistor research
Transistor research at the Institute goes back to the founding director Prof. Joachim Dosse, who published one of the first ever transistor textbooks in German shortly before his appointment to the University of Stuttgart in 1955. Current transistor research at the IHT is divided into research on "Advanced MOS" or field-effect based devices, such as the tunnel transistor (TFET) or high mobility transistors (MODFET), and research on power devices based on bipolar technology, such as the bipolar transistor with insulated gate electrode (IGBT). The research is closely linked to the competence field Group IV Heteroepitaxy and the research of Group IV-based material systems SiGeSn:C, as well as to the competence field Quantum Electronics.
What is behind the TFET vision?
Due to constant miniaturization, quantum mechanical effects are increasingly superimposing the classical behavior of the components. Our goal in nanoelectronics is to exploit quantum mechanical effects and to functionalize them in new device concepts. One example is the tunnel field effect transistor (TFET), a MOS gate controlled Esaki tunnel contact. The current ION when switched on is a gate controlled tunnel current from source to drain contact. Advantages of the tunnel transistor compared to conventional MOS field effect transistors are the low currents IOFF in switched off state, a faster turn-on behavior of the transistor as well as the scalability. However, it has not yet been possible to manufacture a tunnel transistor whose ION current in the switched-on state is high enough to meet the requirements of the semiconductor industry. We are therefore working on systematic geometry and material changes for tunnel transistors with the aim of producing components that outperform conventional MOSFETs.