Device technology

Our work covers device physics and the modelling and manufacture of devices. We are primarily studying silicon and silicon-germanium transistors, although we also study new materials such as silicon carbide (SiC), as well as integrated passive components such as capacitors, resistors and inductances required to build analog circuits.

One important research area is high frequency silicon. CMOS is the dominant technology for the manufacture of circuits and microprocessors, but it has not yet been able to establish itself in the field of analog applications at high frequencies. In research, our challenge is to develop CMOS for use at radio frequencies – RF-CMOS.

In order that the wireless Internet may be successfully developed, it is necessary for CMOS technology to be established in the 5-10 GHz band. Mobile terminals, microwave links and fibre-optic communications will require circuits operating in the frequency band of 60-70 GHz. There will also be a demand for radical new circuit architecture to cope with the demands of RF-CMOS.

Bipolar high frequency silicon is another important area of our work. It deals with the development of bipolar integrated circuits, which combine analog, RF and digital technologies – BiCMOS technology. These combination chips are required for future developments in the mobile application area. The current low transfer rates in mobile telephony will increase from around 10 kb/s today through 1 Mb/s, up to 10 Mb/s in the future. This will place heavy demands on constituent devices.

Silicon carbide (SiC) is a new and promising semiconductor material. We are conducting research into high frequency and high voltage applications for SiC. The material has properties that make it suitable for very high voltages, power and temperature, and also for high frequencies. We are developing funda-mental sub-processes for the manufacture of devices such as etching, metallisation and dielectric deposition, so that we can subsequently combine them into processes for making transistors.

Glossary
CMOS Complementary Metal Oxide Semiconductor - A technology for the manufacture of circuits and microprocessors
BiCMOS Bipolar CMOS
RF Radio Frequency

Contact:  Professor Mikael Östling